Showing papers on "Proteomics published in 1984"
TL;DR: This book is a book that tries to dispel complacency in theoretical ideas, and shows that there are plenty of adventurous ideas in circulation, and the section on the dynamics of biostructure formation does not seem to share any theoretical basis with the study of active transport of ions.
Abstract: It is easy to become complacent in one's theoretical ideas and never take time to think deeply about the kinds of explanation that are possible for muscle contraction, or whatever one's obsession may be. Taking a broader point of view can help to dispel this complacency, and here,is a book .that tries to do so, and shows that there are plenty of adventurous ideas in circulation. It is the photoreproduced typescript report of the proceedings of a symposium held in June 1982 to commemorate the 10th anniversary of the death of Aharon Katzir-Katchalsky. As befits a memorial to such a scientific polymath, the aim of the symposium was broad: to discuss 'directional movement in biological systems: how it is coupled to the driving force, and the structural asymmetry and polarities which are needed to drive it. Such processes include cytoplasmic streaming, active transport of ions across membranes, as well as muscle contraction' and the formation of biological structures. Of course a synthesis of ideas across this broad front was not achieved, nor does it appear to be in sight. As usual the contributors restricted themselves to considering just one of these phenomena. Thus the section on the dynamics of biostructure formation, which is a lively one, and fascinating for an outsider, does not seem to share any theoretical basis with, say, the study of active transport of ions. Some of the ideas current in the study of transport processes are however used also in considering muscle contraction. This has of course been previously emphasized by, for example, T. L. Hill in 1977" and in the present volume the article by S. R. Caplan on the reason for linearity between forces and flows in a coupled system near equilibrium is a stimulant to thinking about muscle contraction, as well as the transport processes to which Caplan has related these ideas. T. L. Hill contributes a carefully explained theoretical treatment of the energetics of 'treadmilling' of microtubules or actin filaments and how mechanical work might be done by these processes, which are perhaps involved in various types of cell motility. Some of the other contributions which I particularly enjoyed were: Carolyn Cohen's thoughtful essay on thin filament regulation in which she emphasizes the importance of considering the dynamic behaviour of the proteins; the explanation by A. Oplatka, R. Levy and J. E. Freidman of why they consider muscle as a kind of rocket engine; Robert
84 citations
TL;DR: The trigger for initiating the expression of embryonic functions is the transfer of cells into fresh medium lacking 2,4-D; the signal is therefore relatively simple and well-defined compared to most animal cell systems.
Abstract: Somatic embryogenesis of carrot cells in culture offers a potentially elegant system for identifying and isolating those gene products with specific roles in development and differentiation. Under the proper conditions, the conversion of cells from non-embryonic to embryonic growth is quantitative, producing yields of early embryos sufficient for biochemical and molecular studies (Sung et al., 1979). The trigger for initiating the expression of embryonic functions is the transfer of cells into fresh medium lacking 2,4-D; the signal is therefore relatively simple and well-defined compared to most animal cell systems. Uniquely and most importantly, the non-embryogenic growth of these cells in suspension cultures supplemented with the synthetic auxin, 2,4dichlorophenoxyacetic acid (2,4-D), provides a good control for cell growth and maintenance functions. Proteins present in embryos but not in the non-embryonic cells are thus more likely to have \"developmental\" functions than \"housekeeping\" functions. Proteins with the opposite behavior, being absent in embryos but present in non-differentiating cells, may also play interesting roles as suppressors of development. Several such \"embryonic\" or \"callus\" proteins have already been identified on native/SDS two-dimensional gels (Sung and Okimoto, 1981
66 citations
TL;DR: The questions addressed and the approaches taken are outlined in the study of carrot embryology, which attempts to outline the questions and approaches taken during the development of somatic embryos.
Abstract: Since Steward and Reinert independently discovered somatic embryogenesis in carrot culture (Reinert, 1959; Steward et al., 1958), it has been a model system for understanding plant embryogenesis. The development of somatic embryos resembles zygotic embryogenesis and exhibits the characteristic morphogenetic stages: globular-, heart-, and torpedostages. Many established cell lines of carrot can produce millions of somatic embryos in liquid cultures that are essentially free of undifferentiated tissues. Embryogenesis can be controlled experimentally to achieve synchronized development; uniform embryonic stages can be isolated en masse (Giuliano et al., 1983). These unique features of carrot culture make possible the study of biochemistry and genetics of early embryogenesis. This paper does not provide a complete review; rather, it attempts to outline the questions addressed and the approaches taken in the study of carrot embryology.
59 citations