The germ-plasm; a theory of heredity, by August Weismann. Tr. by W. Newton Parker and Harriet Rönnfeldt.

Parker, William Newton; Rönnfeldt, Harriet.; Weismann, Auǵust

doi:10.5962/bhl.title.29345

Cited by 5 publications

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“…One of the mechanisms of specification is preformation or autonomous cell specification by the presence of a germ plasm (Figure 2a) in the sex cells of some organisms. Weismann (1885, 1893) identified a specialized region of the cytoplasm of the fertilized oocyte that contained the genetic material necessary and sufficient to direct the specification of PGCs in the embryo. It was later established that the germ plasm contains cytoplasmic determinants that repress transcription in PGCs, which inhibits their ability to respond to inducing signals for their differentiation toward the SC lineage (Nakamura & Seydoux, 2008; Shirae‐Kurabayashi et al, 2011).…”

Section: Pgcs In Vertebratesmentioning

confidence: 99%

Biology of primordial germ cells in vertebrates with emphasis in urodeles amphibians

Porras‐Gómez

Villagrán‐SantaCruz

Moreno‐Mendoza

2021

Molecular Reproduction Devel

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Primordial germ cells (PGCs) are highly specialized cells that play a relevant role in the maintenance and evolution of the species, since they create new combinations of genetic information between the organisms. Amphibians are a class of amniote vertebrates that are divided into three subclasses, the anurans (frogs and toads), the urodeles (salamanders and newts), and the gymnophiones (caecilians). The study of PGCs in amphibians has been addressed in more detail in anurans while little is known about the biology of this cell lineage in urodeles. Studies in some urodeles species have suggested that PGCs are of mesodermal origin, specifying in the lateral plate mesoderm at the late gastrula stage. With classical experiments it shown that, there is an induction of mesoderm, therefore most likely urodeles PGCs develop from unspecialized mesodermal tissue that responds to extracellular signals. However, some fundamental biological processes of PGCs such as the analysis of their specification, arrival, and colonization to the gonads, and their maintenance and differentiation into mature and fertile gametes remain to be elucidated. Therefore, knowledge about the biology of PGCs is of great importance to ensure the perpetuation of urodeles amphibians, as some species are in danger of becoming extinct.

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Section: Pgcs In Vertebratesmentioning

confidence: 99%

Biology of primordial germ cells in vertebrates with emphasis in urodeles amphibians

Porras‐Gómez

Villagrán‐SantaCruz

Moreno‐Mendoza

2021

Molecular Reproduction Devel

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“…Weismann Parker & Rönnfeldt ( 1893 ) state that His's theory of organ‐forming regions was the first, albeit imperfect, expression of the predestination of cells. They argue that His's theory correctly suggests that the ‘differentiating principle’ of development lies within the cell itself and not in external influences (Weismann et al ., 1893 , pp. 134–135).…”

Section: The Influence and Fate Of H Is's Workmentioning

confidence: 99%

The revolutionary developmental biology ofWilhelmHis,Sr.

Richardson

Keuck²

2022

Biological Reviews

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Swiss-born embryologist Wilhelm His, Sr. was the first scientist to study embryos using paraffin histology, serial sectioning and three-dimensional modelling. With these techniques, His made many important discoveries in vertebrate embryology and developmental neurobiology, earning him two Nobel Prize nominations. He also developed several theories of mechanical and evolutionary developmental biology. His argued that adult form is determined by the differential growth of developmental primordia. Furthermore, he suggested that changes in the growth parameters of those primordia are responsible for generating new phenotypes during evolution. His developed these theories in his book 'Our Bodily Form' (Unsere Körperform). Here, we review His's work with special emphasis on its potential importance to the disciplines of evolutionary developmental biology (evo-devo) and mechanobiology.

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Vitalism and the Problem of Individuation: Another Look at Bergson’s Élan Vital

Posteraro

2023

History, Philosophy and Theory of the Life Sciences

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Mikhail Bakhtin’s 1926 essay, “Contemporary Vitalism,” includes Bergson alongside Driesch in a short list of “the most published representatives of vitalism in Western Europe,” and, indeed, Bakhtin’s critique of Driesch is intended to undermine what he calls the “conceptual framework” of “contemporary vitalism” as a whole (The crisis of modernism: Bergson and the vitalist controversy. Eds. Frederick Burwick and Paul Douglass. Cambridge University Press, New York, 1992, p 81). The conceptual framework that Driesch and Bergson are supposed to have shared in common consists at bottom, for Bakhtin, in the ontological commitment to the autonomy of life, “its independence, its disconnectedness from physical-chemical phenomena” (81). This has long been understood as the defining mark of vitalism, at least in the mind of its critics: the contention that matter and the mechanical models that track it are insufficient to the reality of biological forms, and that the explanation of life therefore requires the postulation of a non-mechanical, possibly immaterial, uniquely vital principle, force, substance, or property. Recent scholarship has made considerable headway in complicating these pictures by attending to earlier and subtler forms of materialism, and by distinguishing between different types of vitalism and drawing out the heuristic or scientific utility of some of them (Wolfe, Eidos 14: 212–235, 2011, Antropol Exp 17(13): 215–224, 2017; cf. Wolfe and Normandin, Vitalism and the scientific image in post-enlightenment life science, 1800–2010. Springer, Dordrecht, 2013). The focus of some of this work has been on the critical revaluation of Driesch himself (Bognon et al., Kairos J Philos Sci 20(1): 113–140, 2018). Yet the status of Bergson’s commitment to the existence of a vital principle remains underdeveloped. In the midst of what some are calling a “Bergson renaissance,” I think that it calls for the same kind of critical reappraisal (Ansell-Pearson, Bergson: thinking beyond the human condition. Bloomsbury, New York, 2018: 1; cf. Lundy, Deleuze’s Bergsonism. Edinburgh University Press, Edinburgh, p 5, 2018). The aim of this paper is to attempt the outline of an answer to that call. I begin with a brief summary of Driesch’s vitalism, then I reconstruct Bergson’s underappreciated critique of internal finality, or what Kant called inner purposiveness, and locate in it a subterranean criticism of vital principles of the Drieschian variety as well. Two consequences follow: first, if Bergson is to be considered a vitalist, it cannot be in the Drieschian sense and we are therefore wrong to associate the two; and second, if Bergson is to be considered a vitalist, then his vitalism has to be understood—somewhat counterintuitively, and certainly contra Driesch—on the basis of a principle external to the ostensible individuality of biological forms.

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The germ-plasm; a theory of heredity, by August Weismann. Tr. by W. Newton Parker and Harriet Rönnfeldt.

Cited by 5 publications

References 0 publications

Biology of primordial germ cells in vertebrates with emphasis in urodeles amphibians

Biology of primordial germ cells in vertebrates with emphasis in urodeles amphibians

The revolutionary developmental biology ofWilhelmHis,Sr.

Vitalism and the Problem of Individuation: Another Look at Bergson’s Élan Vital

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