Cytochemical study of the nucleolus of the slime mold Dictyostelium discoideum
The nucleus of the slime mold Dictyostelium discoideum is characterized by the presence of several large dense masses which are all in tight contact with the nuclear membrane. These dense masses, considered as nucleoli, present a rather homogeneous texture, in which dense chromatin, fibrillar, and granular material are not easily detected. The autoradiographic study of (/sup 3/H)uridine pulse-labeled cells showed that the majority of the silver grains were located inside these masses. The use of EDTA regressive-staining, acetylation and enzymatic digestion indicated that they are mostly composed of RNP and are totally devoid of dense chromatin as the rest of the nucleus is. After treatment with actinomycin D, fibrillar and granular material segregated but no chromatin could be found. All these observations confirmed that the dense masses correspond to nucleoli despite their peculiar ultrastructure. It can also be concluded that this type of nucleoli cannot be considered as a taxonomic character of the slime molds because it does not exist in all slime molds and was observed in some dinoflagellates, and ascomycetes.
- Research Organization:
- Departement de Biologie Moleculaire, Institut Pasteur, Paris, France
- OSTI ID:
- 5528209
- Journal Information:
- J. Ultrastruct. Res.; (United States), Vol. 84:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FUNGI
AUTORADIOGRAPHY
NUCLEOLI
ACTINOMYCIN
CHROMATIN
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ULTRASTRUCTURAL CHANGES
URIDINE
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
ANTIMITOTIC DRUGS
ANTINEOPLASTIC DRUGS
AZINES
CELL CONSTITUENTS
DRUGS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MORPHOLOGICAL CHANGES
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PLANTS
PYRIMIDINES
RIBOSIDES
URACILS
550301* - Cytology- Tracer Techniques
550801 - Morphology- Tracer Techniques