Cell Divisions, Duration of Interkinetic States and Differentiation in Early Stages of Embryonic Development

Dettlaff, T. A.

doi:10.1016/b978-1-4831-9950-4.50011-4

Cited by 71 publications

(11 citation statements)

References 51 publications

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“…Also, although in some animal embryos some cell lineages have shorter cell cycles than first to second cleavage, as in leech teloblasts (Bissen and Weisblat 1989), rat primitive streak (MacAuley et al 1993), or early cleavages of axolotl embryos (Hara 1977), the cell cycle from first to second cleavage is among the shortest in the life of most animals and includes the shortest cell cycles recorded for animals. Also, for embryos developing at different temperatures (Detlaff 1964) or for closely related animals (Schneider et al 1992), the duration of other early cell cycles is nearly proportional to duration of this first cell cycle; thus the first cell cycle is representative of rates of early development.…”

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confidence: 99%

Risk and the Evolution of Cell-Cycle Durations of Embryos

2002

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Abstract. Embryos at low risk evolve slower development rates. In seven independent evolutionary contrasts for marine invertebrates (two in asteroids, three in gastropods, one each in phoronids and brachiopods) the more protected embryos had longer cell cycles from first to second cleavage than less protected planktonic embryos. Protected embryos had longer cell cycles even when protected eggs were smaller than planktonic eggs. In an eighth contrast, among tunicates, the embryonic cell cycle was unrelated to brooding and nearly proportional to egg size, but the literature provides examples of especially slow development in some brooding tunicates. The faster development of planktonic embryos is consistent with published estimates of greater mortality rates for planktonic larvae than for embryos in broods or egg masses. Examples from the literature for annelids, arthropods, holothuroids, and chordates also demonstrated longer embryonic cell cycles for more protected embryos with no consistent effect of egg size on cell-cycle duration. Longer cell cycles presumably reduce the benefits of protecting offspring because of longer exposure to whatever hazards remain, but slow development may permit compensating benefits. Hypothesized benefits of longer cell cycles include less maternal investment in rate-limiting materials, more or different transcription, and correction of errors. Such trade-offs are independent of feeding and growth and are influenced by parental protection.

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confidence: 99%

Risk and the Evolution of Cell-Cycle Durations of Embryos

2002

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“…From their data and the present data, we calculated the karyoplasmic ratio for late blastulae, early gastrulae, and early neurulae as 38, 20, and 10, respectively. These values suggest that a stable nucleoctyoplasmic relationship in neurectoderm cells is still not established at the early neurula stage, although DETTLAFF (25) concluded that normal nucleocytoplasmic relationships are established after the blastula stage in amphibian embryos. The heterogeneity in cell size and the karyoplasmic ratio may reflect the degree of cytodifferentiation into nerve cells during primary embryonic induction.…”

Section: Discussionmentioning

confidence: 83%

Cellular Basis of Neuralization of Induced Neurectoderm in Amphibian Embryogenesis: Changes of Cell Shape, Cell Size, and Cytodifferentiation of the Neurectoderm after Neural Induction

Suzuki

Miki

1983

Dev Growth Differ

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Cellular alterations of the neurectoderm after primary embryonic induction were examined by measuring several indices of shape, volume, and cytodifferentiation of the neurectodermal cells of Cynops embryos during gastrulation and early neurulation.Results showed that cellular alterations occurs just after the 18 hr embryo stage (stage 13b). The thickness of the neurectoderm layer decreases like that of the epidermal ectoderm during early and middle gastrulation. After the 18 hr embryo stage, however, the neurectoderm thickens, mainly due to formation of columnar cells. Measurement of cell volume indicates that the neurectoderm of the early and middle gastrulae consists of a cell population of heterogeneous size. The heterogeneity diminishes sharply after the 18 hr embryo stage and the neural plate of the 36 hr embryo (stage 18) consists of cells of homogeneous size.Stages before the 12 hr embryo (stage 12b) and after the 18 hr embryo (stage 13b) also showed differed in cell adhesion to the culture flask and in cytodifferentiating potency. Single cells dissociated from the neurectoderm of 18 hr embryos could adhere to the substratum and differentiate into both nerve-like cells and pigment cells. Both capacities increase during further development.These results are discussed in relation to the neuralizing determination of neurectoderm after primary embryonic induction.

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“…The coexistence of two mechanisms of desynchronization of metabolic activity can explain some experimental results which would seem in apparent contradiction with our theory when only one of these mechanisms is taken into account. For instance, after LiC1 treatment the period of synchronous divisions is lengthened in the sea-urchin egg (results mentioned by Dettlaff, 1964), a feature which would normally result in animMization if LiC1 did not at the same time repress the metabolic activity in the animal region.…”

Section: A Substances Involved In the Initiation Of Autonomous Progrmentioning

confidence: 99%

Cell sociology and the problem of automation in the development of pluricellular animals

Chandebois

1980

Acta Biotheor

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The principles of automation (automatism and programming) in the unfolding of spatiotemporal patterns during animal development are deduced from experimental data reconsidered from the point of view of cell sociology. The developmental programme in the egg is not part of the genetic information but a part of the cytoplasmic information. Throughout development cells store extra-cellular information released by their neighbours in the form of cytoplasmic information. Successive determinations cannot be considered as successive reprogrammings of cells: each one consists of a selection of one specific programme from the total information previously stored. This programme specifies cell interactions in the determined population as a whole; it is very imprecise and is progressively completed during the course of further differentiation by information released by neighbouring cell populations. Complicated patterns may emerge from only two homogeneous populations involved in distinct differentiation pathways and confronting each other. Consequently the "egg developmental programme" provides gene effectors and specific physico-chemical conditions necessary for the staring of at least two distinct differentation pathways. Experimental data suggest that there are two components in this programme. One is a molecular machinery which starts at fertilization in the whole cytoplasm. It yields two programmes of differentiation, typically first an endodermal and then an ectodermal one. The other component of the egg developmental programme, which does not require specific information, allows the interception of the first (endodermal) programme. The application of informatics to developmental automatism is discussed in the latter part of the paper.

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Cell Divisions, Duration of Interkinetic States and Differentiation in Early Stages of Embryonic Development

Cited by 71 publications

References 51 publications

Risk and the Evolution of Cell-Cycle Durations of Embryos

Risk and the Evolution of Cell-Cycle Durations of Embryos

Cellular Basis of Neuralization of Induced Neurectoderm in Amphibian Embryogenesis: Changes of Cell Shape, Cell Size, and Cytodifferentiation of the Neurectoderm after Neural Induction

Cell sociology and the problem of automation in the development of pluricellular animals

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