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...racteristic condensation of chromatin to the nuclear envelope (“margination,” Clifford et al., 1996), DNA fragmentation, and the formation of membrane-enclosed cell fragments called apoptotic bodies (=-=Kerr et al., 1972-=-). Its obviously altruistic function seemed to limit apoptosis to multicellular organisms. Consistently, in a blast database search of the Saccharomyces cerevisiae genome no obvious homologues of any ...

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...ppression and in a wide range of diseases such as AIDS, neurodegenerative processes, and ischemic stroke (Steller, 1995). Apoptotic cells are characterized by a set of distinct morphological changes (=-=Kerr et al., 1972-=-; Wyllie, 1980; Wyllie et al., 1980). An early marker of apoptosis is the exposition of phosphatidylserine on the cell surface, whereas it is normally concentrated in the luminal layer of the cytoplas...

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...theory of aging (see discussion later) summarized critical arguments against the programmed death theory (called Weismann's theory for historical reasons). Here is the partial list of his most forceful critical arguments that have now gained even more strength and support: 1. “The extreme rarity, in natural populations, of individuals that would be old enough to die of the postulated death-mechanism”. 2. “The failure of several decades [now a century! L.A.G. & N.S.G.] of gerontological research to uncover any death-mechanism”; (Note that the later discovery of apoptosis, programmed cell death [80,81], is irrelevant to this discussion focusing on the deathmechanism for the whole organism rather than for some of its somatic cells. It is also important to note that apoptosis is mainly at play during early development and thus is not specific to aging.) Gavrilov and Gavrilova: Evolutionary Theories of Aging TheScientificWorldJOURNAL (2002) 2, 339-356 347 3. “The difficulties involved in visualizing how such a feature [program for death] could be produced by natural selection”. There is, however, one good reason why this defunct theory of programmed death should not be ignored or forgotten, an...

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...istic morphological changes, including plasma membrane blebbing, cell body shrinkage, and formation of membrane-bound apoptotic bodies, which in vivo are quickly engulfed by neighboring healthy cells =-=(103)-=-. Thus, during apoptosis, intracellular contents are not released and potentially harmful inflammatory responses are prevented. Apoptosis is also accompanied by certain biochemical changes, notably th...

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...he organismal level and that the p35 gene constitutes a host range determinant for AcMNPV infection. Apoptosis, a distinctive type of programmed cell death, was first described in 1972 by Kerr et al. =-=(22)-=- and is now widely recognized as being vital to a diversity of biological processes, including embryonic development, tissue homeostasis, tumorigenesis, and the lysis of virally infected cells by cyto...

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... by oil immersion light microscopy at a final magnification of 400. All samples were coded, and 9500 cells per slide were examined. Apoptotic cells were identified according to the following criteria =-=(25)-=-: condensed and fragmented nuclei, blebbing of plasma membranes, and decrease in cell size. DNA Fragmentation Fragmented and intact DNA were evaluated as described (5). Suspended EC (5 × 105) were cen...

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...aintenance of the tissues and organs of vertebrates (Gliicksmann, 1951). Naturally occurring cell death helps to establish and maintain the functional properties oftissues and organs (Saunders, 1966; =-=Kerr et al., 1972-=-) and presumably developed because it conferred an evolutionary advantage to the organism (Umansky, 1982). Cell death is often controlled by survival-promoting signals from other cells (for concise re...

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...iber differentiation is not simply PCD, since the outcome is very different from that of classical PCD, where the cell usually shrinks, frequently fragments, and is rapidly phagocytosed and digested (=-=Kerr et al., 1972-=-; Wyllie et al., 1980); a lens fiber, by contrast, elongates, fills up with crystallins, and persists for the lifetime of the animal. Taken together, our results provide strong evidence that the diffe...

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...tivation,DNA fragmentation, cytoplasmicblebbing, and phagocyte engulfment of the apoptotic cell such that completedegradation of thecell requires theengulfing cell’s lysosomalmachinery (Clarke, 1990; =-=Kerr et al., 1972-=-). In contrast, cells that die with an autophagic cell death morphology are capable of digesting their own contents without the aid of engulfing phagocytes (Clarke, 1990; Martin and Baehrecke, 2004). ...