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.

Apoptosis in Degenerative Diseases of the Basal Ganglia

1998 ◽  
Vol 4 (4) ◽  
pp. 301-311 ◽  
Author(s):  
Robert E. Burke
Keyword(s):  
Cell Death ◽  
Basal Ganglia ◽  
Programmed Cell Death ◽  
Direct Evidence ◽  
Normal Development ◽  
Dopamine Neurons ◽  
Degenerative Diseases ◽  
Morphological Markers ◽  
Degenerative Disorders ◽  
New Hypothesis

Degenerative disorders of the basal ganglia are characterized by disturbances of motor control. Prototypic examples are Parkinson's disease, which is caused by degeneration of dopamine neurons of the substantia nigra, and Huntington's disease, which is caused by degeneration of neurons of the striatum. In recent years, it has been postulated that some of these disorders may be caused by programmed cell death or apoptosis, a genetically regulated form of cell death. There is clear evidence that apoptosis occurs in neurons of the basal ganglia during normal development, that it can be regulated, and that it can be induced in some animal models of these disorders. Although there is some suggestive direct evidence that apoptosis may occur in the human brain in these disorders, the evidence to date is partial and not yet compelling. Nevertheless, programmed cell death is an important new hypothesis for the pathogenesis of these disorders and warrants vigorous further investigation, particularly with molecular markers in addition to classic morphological markers. The concept of programmed cell death is relevant not only to the pathogenesis of these diseases but also to therapeutic issues, such as transplantation approaches.

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

Insights into chaperonin function from studies on archaeal thermosomes

2011 ◽  
Vol 39 (1) ◽  
pp. 94-98 ◽  
Author(s):  
Peter Lund
Keyword(s):  
Cell Death ◽  
Protein Folding ◽  
Recent Work ◽  
Mechanism Of Action ◽  
Molecular Chaperones ◽  
Short Review ◽  
Living Cells ◽  
Living Organisms ◽  
Opening And Closing ◽  
Hydrolysis Of

It is now well understood that, although proteins fold spontaneously (in a thermodynamic sense), many nevertheless require the assistance of helpers called molecular chaperones to reach their correct and active folded state in living cells. This is because the pathways of protein folding are full of traps for the unwary: the forces that drive proteins into their folded states can also drive them into insoluble aggregates, and, particularly when cells are stressed, this can lead, without prevention or correction, to cell death. The chaperonins are a family of molecular chaperones, practically ubiquitous in all living organisms, which possess a remarkable structure and mechanism of action. They act as nanoboxes in which proteins can fold, isolated from their environment and from other partners with which they might, with potentially deleterious consequences, interact. The opening and closing of these boxes is timed by the binding and hydrolysis of ATP. The chaperonins which are found in bacteria are extremely well characterized, and, although those found in archaea (also known as thermosomes) and eukaryotes have received less attention, our understanding of these proteins is constantly improving. This short review will summarize what we know about chaperonin function in the cell from studies on the archaeal chaperonins, and show how recent work is improving our understanding of this essential class of molecular chaperones.

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 Normal development, oncogenesis and programmed cell death

Oncogene ◽  
1998 ◽  
Vol 17 (10) ◽  
pp. 1189-1194 ◽  
Author(s):  
Dan A Liebermann
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Normal Development

scholarly journals The Reaper-Binding Protein Scythe Modulates Apoptosis and Proliferation during Mammalian Development

2005 ◽  
Vol 25 (23) ◽  
pp. 10329-10337 ◽  
Author(s):  
Fabienne Desmots ◽  
Helen R. Russell ◽  
Youngsoo Lee ◽  
Kelli Boyd ◽  
Peter J. McKinnon
Keyword(s):  
Cell Death ◽  
Drosophila Melanogaster ◽  
Programmed Cell Death ◽  
Xenopus Laevis ◽  
Cellular Proliferation ◽  
Nuclear Protein ◽  
Normal Development ◽  
Mammalian Development ◽  
Developmental Defects ◽  
Cell Extracts

ABSTRACT Scythe (BAT3 [HLA-B-associated transcript 3]) is a nuclear protein that has been implicated in apoptosis, as it can modulate Reaper, a central apoptotic regulator in Drosophila melanogaster. While Scythe can markedly affect Reaper-dependent apoptosis in Xenopus laevis cell extracts, the function of Scythe in mammals is unknown. Here, we report that inactivation of Scythe in the mouse results in lethality associated with pronounced developmental defects in the lung, kidney, and brain. In all cases, these developmental defects were associated with dysregulation of apoptosis and cellular proliferation. Scythe − / − cells were also more resistant to apoptosis induced by menadione and thapsigargin. These data show that Scythe is critical for viability and normal development, probably via regulation of programmed cell death and cellular proliferation.

scholarly journals Somaclonal Variation During Picea abies and P. omorika Somatic Embryogenesis and Cryopreservation

2017 ◽  
Vol 59 (1) ◽  
pp. 93-103 ◽  
Author(s):  
Teresa Hazubska-Przybył ◽  
Monika Dering
Keyword(s):  
Somatic Embryogenesis ◽  
Picea Abies ◽  
Somaclonal Variation ◽  
Genetic Stability ◽  
Somatic Embryos ◽  
Plant Material ◽  
Stress Factors ◽  
Embryogenic Cultures ◽  
Embryogenic Lines

AbstractEmbryogenic cultures of plants are exposed to various stress factors bothin vitroand during cryostorage. In order to safely include the plant material obtained by somatic embryogenesis in combination with cryopreservation for breeding programs, it is necessary to monitor its genetic stability. The aim of the present study was the assessment of somaclonal variation in plant material obtained from embryogenic cultures ofPicea abies(L.) Karst. andP. omorika(Pančić) Purk. maintainedin vitroor stored in liquid nitrogen by the pregrowth-dehydration method. The analysis of genetic conformity with using microsatellite markers was performed on cotyledonary somatic embryos (CSE), germinating somatic embryos (GSE) and somatic seedlings (SS), obtained from tissues maintainedin vitroor from recovered embryogenic tissues (ETc) and CSE obtained after cryopreservation. The analysis revealed changes in the DNA of somatic embryogenesis-derived plant material of bothPiceaspp. They were found in plant material from 8 out of 10 tested embryogenic lines ofP. abiesand in 10 out of 19 embryogenic lines ofP. omorikaafterin vitroculture. Changes were also detected in plant material obtained after cryopreservation. Somaclonal variation was observed in ETc and CSE ofP. omorikaand at ETv stage ofP. abies. However, most of the changes were induced at the stage of somatic embryogenesis initiation. These results confirm the need for monitoring the genetic stability of plants obtained by somatic embryogenesis and after cryopreservation for both spruce species.

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.

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