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.

scholarly journals Mechanisms of programmed cell death

2019 ◽  
Vol 6 (4) ◽  
pp. 156-158
Author(s):  
Abdu-Alhameed A Ali Azzwali ◽  
 Azab Elsayed Azab
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Nuclear Dna ◽  
Chromatin Condensation ◽  
Cell Shrinkage ◽  
Membrane Blebbing ◽  
Development And Aging ◽  
Nuclear Dna Fragmentation ◽  
Dependent Pathway

The present review aims to spotlight on the mechanisms and stages of programmed cell death. Apoptosis, known as programmed cell death, is a homeostatic mechanism that generally occurs during development and aging in order to keep cells in tissue. It can also act as a protective mechanism, for example, in immune response or if cells are damaged by toxin agents or diseases. In cancer treatment, drugs and irradiation used in chemotherapy leads to DNA damage, which results in triggering apoptosis through the p53 dependent pathway in cancer treatment, drugs and irradiation used in chemotherapy leads to DNA damage, which results in triggering apoptosis through the p53 dependent pathway. Corticosteroids can cause apoptotic death in a number of cells. A number of changes in cell morphology are related to the different stages of apoptosis, which includes nuclear DNA fragmentation, cell shrinkage, chromatin condensation, membrane blebbing, and the formation of apoptotic bodies. There are three pathways for apoptosis, the intrinsic (mitochondrial) and extrinsic (death receptor) are the two major paths that are interlinked and that can effect one another. Conclusion: It can be concluded that apoptosis is a homeostatic mechanism that generally occurs during development and aging in order to keep cells in tissue. Drugs and irradiation used in chemotherapy leads to DNA damage, which results in triggering apoptosis through the p53 dependent pathway. The apoptosis, stages are includes nuclear DNA fragmentation, cell shrinkage, chromatin condensation, membrane blebbing, and the formation of apoptotic bodies. There are three pathways for apoptosis.

scholarly journals Have necrohormones a role in embryogenesis?

2014 ◽  
Vol 65 (1-2) ◽  
pp. 7-9 ◽  
Author(s):  
P. R. Bell
Keyword(s):  
Cell Death ◽  
Somatic Embryogenesis ◽  
Programmed Cell Death ◽  
Picea Abies ◽  
Recent Work ◽  
Normal Development ◽  
Living Cells ◽  
Embryogenic Cultures ◽  
Conflicting Evidence ◽  
Apomictic Reproduction

The recognition of apoptosis (programmed cell death) as an accompaniment of normal development, the products released by the protoplasts undergoing self-destruction being utilized by adjacent living cells, stimulates renewed interest in Haberlandt's concept of "necrohormones" playing a role in apomictic reproduction. Recent work on somatic embryogenesis in carrot shows that regular death of certain cells in embryogenic cultures satifies the criteria of apoptosis. Similar observations have been made with embryogenic cultures of <em>Picea abies</em>. Haberlandt's claim that cell death induced by injury adjacent to an ovule in <em>Oenothera</em> could lead to parthenogenesis, despite conflicting evidence from later experimenters, is worthy of reexamination.

Widespread programmed cell death in proliferative and postmitotic regions of the fetal cerebral cortex

Development ◽  
1996 ◽  
Vol 122 (4) ◽  
pp. 1165-1174 ◽  
Author(s):  
A.J. Blaschke ◽  
K. Staley ◽  
J. Chun
Keyword(s):  
Cell Death ◽  
Cerebral Cortex ◽  
Programmed Cell Death ◽  
Nuclear Dna ◽  
Temporal Distribution ◽  
Embryonic Cell ◽  
Postnatal Life ◽  
Neuron Development ◽  
Cortical Cells ◽  
Dying Cells

A key event in the development of the mammalian cerebral cortex is the generation of neuronal populations during embryonic life. Previous studies have revealed many details of cortical neuron development including cell birthdates, migration patterns and lineage relationships. Programmed cell death is a potentially important mechanism that could alter the numbers and types of developing cortical cells during these early embryonic phases. While programmed cell death has been documented in other parts of the embryonic central nervous system, its operation has not been previously reported in the embryonic cortex because of the lack of cell death markers and the difficulty in following the entire population of cortical cells. Here, we have investigated the spatial and temporal distribution of dying cells in the embryonic cortex using an in situ endlabelling technique called ‘ISEL+’ that identifies fragmented nuclear DNA in dying cells with increased sensitivity. The period encompassing murine cerebral cortical neurogenesis was examined, from embryonic days 10 through 18. Dying cells were rare at embryonic day 10, but by embryonic day 14, 70% of cortical cells were found to be dying. This number declined to 50% by embryonic day 18, and few dying cells were observed in the adult cerebral cortex. Surprisingly, while dying cells were observed throughout the cerebral cortical wall, the majority were found within zones of cell proliferation rather than in regions of postmitotic neurons. These observations suggest that multiple mechanisms may regulate programmed cell death in the developing cortex. Moreover, embryonic cell death could be an important factor enabling the selection of appropriate cortical cells before they complete their differentiation in postnatal life.

scholarly journals Ca2+-dependent nuclease is involved in DNA degradation during the formation of the secretory cavity by programmed cell death in fruit of Citrus grandis ‘Tomentosa’

2020 ◽  
Vol 71 (16) ◽  
pp. 4812-4827 ◽  
Author(s):  
Mei Bai ◽  
Minjian Liang ◽  
Bin Huai ◽  
Han Gao ◽  
Panpan Tong ◽  
...  
Keyword(s):  
Cell Death ◽  
In Situ Hybridization ◽  
Programmed Cell Death ◽  
Nuclear Dna ◽  
Expression Patterns ◽  
Citrus Fruit ◽  
Dna Degradation ◽  
Secretory Cavity ◽  
Spatio Temporal

Abstract The secretory cavity is a typical structure in Citrus fruit and is formed by schizolysigeny. Previous reports have indicated that programmed cell death (PCD) is involved in the degradation of secretory cavity cells in the fruit, and that the spatio-temporal location of calcium is closely related to nuclear DNA degradation in this process; however, the molecular mechanisms underlying this Ca2+ regulation remain largely unknown. Here, we identified CgCaN that encodes a Ca2+-dependent DNase in the fruit of Citrus grandis ‘Tomentosa’, the function of which was studied using calcium ion localization, DNase activity assays, in situ hybridization, and protein immunolocalization. The results suggested that the full-length cDNA of CgCaN contains an ORF of 1011 bp that encodes a protein 336 amino acids in length with a SNase-like functional domain. CgCaN digests dsDNA at neutral pH in a Ca2+-dependent manner. In situ hybridization signals of CgCaN were particularly distributed in the secretory cavity cells. Ca2+ and Ca2+-dependent DNases were mainly observed in the condensed chromatin and in the nucleolus. In addition, spatio-temporal expression patterns of CgCaN and its protein coincided with the time-points that corresponded to chromatin degradation and nuclear rupture during the PCD in the development of the fruit secretory cavity. Taken together, our results suggest that Ca2+-dependent DNases play direct roles in nuclear DNA degradation during the PCD of secretory cavity cells during Citrus fruit development. Given the consistency of the expression patterns of genes regulated by calmodulin (CaM) and calcium-dependent protein kinases (CDPK) and the dynamics of calcium accumulation, we speculate that CaM and CDPK proteins might be involved in Ca2+ transport from the extracellular walls through the cytoplasm and into the nucleus to activate CgCaN for DNA degradation.

Hemoglobins, programmed cell death and somatic embryogenesis

Plant Science ◽  
2013 ◽  
Vol 211 ◽  
pp. 35-41 ◽  
Author(s):  
Robert D. Hill ◽  
Shuanglong Huang ◽  
Claudio Stasolla
Keyword(s):  
Cell Death ◽  
Somatic Embryogenesis ◽  
Programmed Cell Death

Patterning during somatic embryogenesis in Scots pine in relation to polar auxin transport and programmed cell death

2011 ◽  
Vol 109 (3) ◽  
pp. 391-400 ◽  
Author(s):  
Malin Abrahamsson ◽  
Silvia Valladares ◽  
Emma Larsson ◽  
David Clapham ◽  
Sara von Arnold
Keyword(s):  
Cell Death ◽  
Somatic Embryogenesis ◽  
Programmed Cell Death ◽  
Scots Pine ◽  
Auxin Transport ◽  
Polar Auxin Transport

scholarly journals Identification of programmed cell death in situ via specific labeling of nuclear DNA fragmentation.

1992 ◽  
Vol 119 (3) ◽  
pp. 493-501 ◽  
Author(s):  
Y Gavrieli ◽  
Y Sherman ◽  
S A Ben-Sasson
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Dna Fragmentation ◽  
Nuclear Dna ◽  
Nuclear Periphery ◽  
Lymphoid Tissues ◽  
Pooled Dna ◽  
Nuclear Dna Fragmentation ◽  
Small And Large Intestine

Programmed cell death (PCD) plays a key role in developmental biology and in maintenance of the steady state in continuously renewing tissues. Currently, its existence is inferred mainly from gel electrophoresis of a pooled DNA extract as PCD was shown to be associated with DNA fragmentation. Based on this observation, we describe here the development of a method for the in situ visualization of PCD at the single-cell level, while preserving tissue architecture. Conventional histological sections, pretreated with protease, were nick end labeled with biotinylated poly dU, introduced by terminal deoxy-transferase, and then stained using avidin-conjugated peroxidase. The reaction is specific, only nuclei located at positions where PCD is expected are stained. The initial screening includes: small and large intestine, epidermis, lymphoid tissues, ovary, and other organs. A detailed analysis revealed that the process is initiated at the nuclear periphery, it is relatively short (1-3 h from initiation to cell elimination) and that PCD appears in tissues in clusters. The extent of tissue-PCD revealed by this method is considerably greater than apoptosis detected by nuclear morphology, and thus opens the way for a variety of studies.

Role of hydrogen peroxide in stress-induced programmed cell death during somatic embryogenesis in Fraxinus mandshurica

2019 ◽  
Vol 30 (3) ◽  
pp. 767-777 ◽  
Author(s):  
Ling Yang ◽  
Cheng Wei ◽  
Chao Huang ◽  
Hongnan Liu ◽  
Dongyan Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Death ◽  
Somatic Embryogenesis ◽  
Programmed Cell Death ◽  
Fraxinus Mandshurica
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