International Society for History, Philosophy, and Social Studies of Biology


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Program

TUESDAY, JULY 7  /  11:00 - 12:30  /  DS-R520
Organized session / standard talks
Thinking about cells (1): What are cells and how do we know?
Organizer(s):

Jane Maienschein (Arizona State University, United States); Karl Matlin (University of Chicago, United States)

These two coordinated sessions look at what cells are and how they work, in parallel with consideration of epistemological questions about how we know. The first session examines the evolving understanding of what cells are, including an overview of early concepts and close examination of studies in protozoa and in stem cells. Throughout, we ask about the methods and assumptions involved. The second session turns to questions about how cells work. This includes a look at explorations of cytoplasmic streaming within cells, at the understanding of cell death, and at intersections of form and function through study of mitochondria and oxidative phosphorylation. Here issues of methods, metaphor, and the heuristic use of form in order to inform mechanical explanations of function play important roles. The sessions work together to get at historical, philosophical, and biological questions about cells.


A century of cells

Jane Maienschein (Arizona State University, United States)

Schleiden and Schwann had a very different concept of cells than the team of authors Edmund Cowdry brought together for General Cytology or Special Cytology in the 1920s. The first cell theory saw cells as a structural unit of organisms. It was not the only unit, and organisms did not consist of cells alone. By the end of the 19th century, the cell had become the fundamental structural and functional unit for living systems. In addition, the cell was clearly alive itself, with the capacity to reproduce and differentiate. By the mid-20th century, cells were thought also to go through life cycles and to undergo senescence and death. “The cell” gave way to a diversity of different kinds of cells, each with different properties and behaviors. By a century after Schleiden’s and Schwann’s initial cell theory, the concept of cells looked very different. This presentation will look more closely at major shifts in our understanding, and what provoked those changes.


Cell heredity, epigenetics, and structural inheritance

Jan Sapp (York University, Canada)

My presentation focuses on discussions and experiments in protozoan genetics beginning in the 1950s concerning two aspects of cell heredity, epigenetics, and structural inheritance, each of which focused on different problems of the cell in development and heredity. Although the term “epigenetics” (though not “epigenetic”) is often traced to Waddington (1942), the term “epigenetics” in the sense of inherited changes resulting from the regulation of genes, as it is used today, is rooted in microbial geneticists’ experiments and discussions of cell heredity in the 1950s, and their attempts to bridge genetics and embryology. Epigenetic inheritance was introduced by microbial geneticists to resolve what is commonly referred to as the paradox of cellular differentiation in the face of nuclear equivalence. A second research program based on ciliated protists, aimed at resolving another long-standing problem of morphogenesis, began in the 1960s based on experimental demonstrations of “structural inheritance” not involving gene regulation. One form of structural inheritance involves the cell cortex acting as scaffolding for the assembly of gene products; the explanation for a second less well known form of structural inheritance (or field heredity) remains uncertain. As we shall see, biologists' conceptions of the cell are still in the making.


What can we learn from stem cells? Induced pluripotent stem cells as models in cancer research

Lucie Laplane (Institut Gustave Roussy, France); Allan Beke (Institut Gustave Roussy, France)

Since the rise of the cell theory in the 19th century, the cell has been considered as a unit of structure, function, and reproduction. Cells are the elementary building block of life. Among cells, stem cells play a particular role and might be “units of development,” “units of regeneration,” and even “units in evolution” (Weissman 2000). What can we learn from those cells? And does stemness make stem cells a unit of particular interest for the explanation of some biological properties? In this presentation, we will focus on the case of induced pluripotent stem cells (iPSC) in oncology. It is now possible to generate pluripotent stem cells from patient cancer cells. Those cancerous iPSC then provide an unlimited resource of cancer cells to study and experiment with. The introduction of iPSC technology in oncology raises the question of whether and how it provides an adequate tool to model, experiment, understand, and cure cancers. We will first highlight the advantages and pitfalls of the introduction of iPSC as a new model in oncology, and then highlight the role of stemness in the ability of iPSC to model cancers.