Extra DNA synthesis in embryo suspensor cells ofPhaseolus coccineus

PROTOPLASMA ◽  
1977 ◽  
Vol 91 (3) ◽  
pp. 303-313 ◽  
Author(s):  
R. Cremonini ◽  
P. G. Cionini
Keyword(s):  
Dna Synthesis ◽  
Embryo Suspensor ◽  
Suspensor Cells

Cytological localization of thePGIP genes in the embryo suspensor cells ofPhaseolus vulgavis L

1993 ◽  
Vol 87 (3) ◽  
pp. 369-373 ◽  
Author(s):  
M. Frediani ◽  
R. Cremonini ◽  
G. Salvi ◽  
C. Caprari ◽  
A. Desiderio ◽  
...  
Keyword(s):  
Embryo Suspensor ◽  
Cytological Localization ◽  
Suspensor Cells

Two waves of programmed cell death occur during formation and development of somatic embryos in the gymnosperm, Norway spruce

2000 ◽  
Vol 113 (24) ◽  
pp. 4399-4411 ◽  
Author(s):  
L.H. Filonova ◽  
P.V. Bozhkov ◽  
V.B. Brukhin ◽  
G. Daniel ◽  
B. Zhivotovsky ◽  
...  
Keyword(s):  
Cell Death ◽  
Somatic Embryogenesis ◽  
Programmed Cell Death ◽  
Norway Spruce ◽  
Somatic Embryos ◽  
Nuclear Dna ◽  
Second Phase ◽  
Embryo Suspensor ◽  
Large Central Vacuole ◽  
Suspensor Cells

In the animal life cycle, the earliest manifestations of programmed cell death (PCD) can already be seen during embryogenesis. The aim of this work was to determine if PCD is also involved in the elimination of certain cells during plant embryogenesis. We used a model system of Norway spruce somatic embryogenesis, which represents a multistep developmental pathway with two broad phases. The first phase is represented by proliferating proembryogenic masses (PEMs). The second phase encompasses development of somatic embryos, which arise from PEMs and proceed through the same sequence of stages as described for their zygotic counterparts. Here we demonstrate two successive waves of PCD, which are implicated in the transition from PEMs to somatic embryos and in correct embryonic pattern formation, respectively. The first wave of PCD is responsible for the degradation of PEMs when they give rise to somatic embryos. We show that PCD in PEM cells and embryo formation are closely interlinked processes, both stimulated upon withdrawal or partial depletion of auxins and cytokinins. The second wave of PCD eliminates terminally differentiated embryo-suspensor cells during early embryogeny. During the dismantling phase of PCD, PEM and embryo-suspensor cells exhibit progressive autolysis, resulting in the formation of a large central vacuole. Autolytic degradation of the cytoplasm is accompanied by lobing and budding-like segmentation of the nucleus. Nuclear DNA undergoes fragmentation into both large fragments of about 50 kb and multiples of approximately 180 bp. The tonoplast rupture is delayed until lysis of the cytoplasm and organelles, including the nucleus, is almost complete. The protoplasm then disappears, leaving a cellular corpse represented by only the cell wall. This pathway of cell dismantling suggests overlapping of apoptotic and autophagic types of PCD during somatic embryogenesis in Norway spruce.

Cytochemical and Autoradiographic Analyses on the Embryo Suspensor Cells ofPhaseolus Coccineos

Caryologia ◽  
1970 ◽  
Vol 23 (4) ◽  
pp. 605-638 ◽  
Author(s):  
S. Avanzi ◽  
P. G. Cionini ◽  
F. D'Amato
Keyword(s):  
Embryo Suspensor ◽  
Suspensor Cells

Use of Antibody to aid Visualization of Protein at the Termini of Bacteriophage Ø29 DNA

1980 ◽  
Vol 38 ◽  
pp. 540-541
Author(s):  
Dwight Anderson ◽  
Charlene Peterson ◽  
Gursaran Notani ◽  
Bernard Reilly
Keyword(s):  
Electron Microscopy ◽  
Bacillus Subtilis ◽  
Dna Synthesis ◽  
Restriction Endonuclease ◽  
Protein Complex ◽  
Protein Product ◽  
Viral Dna ◽  
Small Proteins ◽  
Antibody Labeling ◽  
Subtilis Bacteriophage

The protein product of cistron 3 of Bacillus subtilis bacteriophage Ø29 is essential for viral DNA synthesis and is covalently bound to the 5’-termini of the Ø29 DNA. When the DNA-protein complex is cleaved with a restriction endonuclease, the protein is bound to the two terminal fragments. The 28,000 dalton protein can be visualized by electron microscopy as a small dot and often is seen only when two ends are in apposition as in multimers or in glutaraldehyde-fixed aggregates. We sought to improve the visibility of these small proteins by use of antibody labeling.

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