![]() in Chinese hamster ovary (CHO) cells, were compared with the phenomenon of premature mitosis or mitotic catastrophe. Īpoptotic events of chromatin condensation, as described in detail by Banfalvi et al. Ultrastructural changes observed in a plant cell during AL-PCD are classified as follows: (i) compaction and vacuolization of the cytoplasm, (ii) specific fragmentation of the cytoplasm and unique single-membrane vesicles containing the active organelles in a vacuole, (iii) intensive synthesis of mitochondrial DNA in vacuolar vesicles, (iv) cessation of nuclear DNA synthesis, (v) condensation and marginalization of chromatin inside the nucleus, and (vi) internucleosomal fragmentation of nuclear DNA. Research clearly shows that AL-PCD is an integral part of plant ontogenesis controlled by cellular oxidative state, phytohormones, and DNA methylation. Due to the fact that some specific symptoms have also been observed in plants, the term apoptosis-like programmed cell death (AL-PCD) has been introduced. The biggest controversies arouse over apoptosis, as until recently it was believed to be absent from plants. It has also been confirmed that some symptoms of autophagy in animal cells are identical with those of autolytic plant PCD. Detailed analysis has revealed an analogy between necrosis and non-autolytic plant PCD. Īttempts to unify PCD terminology concerning animal and plant cells has not been easy and is mainly limited by cell structure disparities. Autolytic plant PCD is associated with hydrolases being released from a vacuole after its collapse, thus resulting in rapid clearance of the cytoplasm. The presence of vacuoles and additional organelles can also impact the process. The existence of cell wall in plants makes phagocythosis impossible, therefore an additional process of apoptotic bodies degradation is needed for the adjacent cells to be able to start collecting the remains. The main dispartity between plants and animals is the mechanism of cell debris removal following cell death. ![]() Due to divergencies in biochemical mechanisms and morphological cell changes, there are three types of PCD distinguished in animals: apoptosis (Type I of PCD), autophagy (Type II od PCD) and necrosis and two major types in plants: autolytic (vacuolar) and non-autolytic (necrotic), which differ in terms of cytoplasm destruction. ĭifferencies regarding PCD that can be observed between animals and plants or even within these groups make description of this process difficult. PCD associated with cell differentiation is known as developmental cell death (DCD). Cell dying is one of the most complicated processes to follow due to the diversity of stimuli that may influence it, as well as regulatory mechanisms responsible for cell destruction and final removal. PCD is a natural consequence of ageing, but it also may be switched on by either environmental stress factors or developmental irregularities. It is a unique set of events that lead to controlled and organized destruction of redundant, damaged or nonfunctional cells. In order to preserve a specific cell number and maintain organism balance, cells are equipped with a genetically designed mechanism known as programmed cell death (PCD). The results obtained have been discussed with respect to the vacuolar/autolytic type of plant-specific AL-PCD. In addition, the results obtained under transmission electron microscopy (TEM) further revealed apoptotic-like features at the ultrastructural level of PCC-type cells: (i) extensive vacuolization (ii) abnormal chromatin condensation, its marginalization and concomitant degradation (iii) formation of autophagy-like vesicles (iv) protoplast shrinkage (v) fragmentation of cell nuclei and (vi) extensive degeneration of the cells. Apoptotic-type DNA fragmentation and positive TUNEL reaction finally proved that CF triggers AL-PCD in stressed V. Acridine orange and ethidium bromide (AO/EB) were applied for quantitative immunofluorescence measurements of dead, dying and living cells. The immunocytochemical detection of H2AXS139Ph and PARP-2 were used as markers for DSBs and SSBs, respectively. A single chromosome comet assay was successfully used to study different types of DNA damage (neutral variant–DSBs versus alkaline–DSBs or SSBs). Initiation of the apoptotic-like cell degradation pathway seemed to be the result of DNA damage generated by treatment with hydroxyurea (HU) and co-treatment with HU/CF. We have demonstrated that the activation of apoptosis-like programmed cell death (AL-PCD) was a secondary result of caffeine (CF) induced premature chromosome condensation (PCC) in hydroxyurea-synchronized Vicia faba root meristem cells.
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