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Biomedical subjects

E G Jordan

Publications and source records attributed to E G Jordan.

26 records · Page 2Linked to original sources
PubMed1977

The nucleolus and meiosis during microsporogenesis in Endymion non-scriptus (L.).

Stages of meiosis from the bluebell Endymion non-scriptus (L.) were studied by electron microscopy. The segregated components of the nucleolus at meiotic prophase underwent fragmentation and dissolution at pachytene-diplotene. Nucleoli were absent during both meiotic divisions and reformed on the nucleolus organizer into a fibrillar mass from scattered fibrillar components at the dyad and tetrad stages. Ti is argued that the fibrillar region shows continuity through nuclear division though undergoing structural transformations in the process. Nucleolar reformation occurs on condensed nucleolus organizers. Processing of the ribosomal precursors and the resumption of RNA synthesis is discussed in relation to the dispersal of the nucleolus organizer into the fibrillar region of the reformed nucleolus.

Cell Nucleolus↗
PubMed1976

The presentation of three-dimensional reconstructions from serial sections.

A simple and effective way is described for showing particular structures in serial sections. By using waterproof inks and acetate sheets supported on a frame immersed in water and illuminated from beneath, the information from up to sixty sections can be easily visualized. This technique is particularly useful for displaying enclosed structures and by a suitable choice of colours enables special emphasis to be given to selected components. The information can be recorded simply through stereo photography.

Models, Structural↗
PubMed1976

The nucleolus organizer and the synaptonemal complex in Endymion non-scriptus (L.).

Stages of meiosis from the bluebell Endymion non-scriptus (L.) were studied by electron microscopy. The nucleolus went through the process of segregation at the beginning of meiosis with the movement to its surface of a pale-staining region. This region was shown to be the same as that called the 'L zone' or lacunae of nucleoli. Its chromosomal nature was strongly suggested by the presence of the synaptonemal complex within it. This demonstrated that the pale-staining region of nucleoli is the nucleolus organizer and almost certainly the chromosome region containing the ribosomal cistrons, and justifies the use of these terms to describe the structure when seen inside the nucleolus. The relationship between this zone and the heterochromatic knob called the nucleolar organizing body in maize by other workers is discussed.

Cell Nucleolus↗