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Cell Biology International Jul 2012Recent investigations give reason to question anew the historical status of the 'cell theory' as the ultimate driving force in the development of our understanding of... (Review)
Review
Recent investigations give reason to question anew the historical status of the 'cell theory' as the ultimate driving force in the development of our understanding of life's processes at the most fundamental level. A revisitation of critical research papers and commentaries from the 19th Century shows that the disregarded (and historically maligned) 'protoplasmic theory of life' played a more deterministic role in the early advancement of knowledge on cell structure and function.
Topics: Cell Biology; Cytoplasm; History, 19th Century; Models, Molecular
PubMed: 22681391
DOI: 10.1042/CBI20120128 -
Physiological Chemistry and Physics and... 2007Among the most promising scientific achievements of the 19th century was the recognition that the laws governing the dead world also govern the world of the living and... (Review)
Review
Among the most promising scientific achievements of the 19th century was the recognition that the laws governing the dead world also govern the world of the living and that life has a physical basis called protoplasm. Regrettably, the definition of protoplasm provided then was (inescapably) incorrect, offering a (legitimate) reason for rejecting the concept of protoplasm by an overwhelming majority of later investigators, teachers and other opinion-makers. Without a recognized physical basis, Life itself also faded into the limbo of the unexplainable. However, eventually the needed relevant parts of physics and chemistry to give a more cogent definition of protoplasm became available. That then made possible the construction in the early 1960's of a unifying theory of the living cell, named the association-induction (AI) hypothesis. Historically speaking, the AI Hypothesis is the heir to the general concept of protoplasm as the physical basis of life-incorrect as the initial definition of protoplasm was notwithstanding. In the AI Hypothesis (AIH) the true or ultimate physical basis of life is not what the advocates of the protoplasm once considered as the physical basis of life. What they saw and construed as the physical basis of life is a particular kind of macroscopic protoplasm. In the AI Hypothesis, the basic unit (or physical basis) of life is microscopic protoplasm or nano-protoplasm, of which all macroscopic protoplasm is made. The AI Hypothesis also had no difficulty offering a new definition to what life is in terms of fundamental physical-chemical laws. Nano-protoplasm is defined by what it is and what it does. In greater detail, it is defined (i) by its chemical composition given in Equation 1 on p. 124; (ii) by the mutual spatial and energetic relationships among the components as illustrated diagrammatically in Figure 5 on p. 125; and (iii) by the ability of these components to exist as coherent assemblies in either one of two alternative states, the resting and active living (or dead) state as according to Equation 5 on p. 142. The review then describes the AIH-based electronic and molecular mechanisms for the coherent assemblage of the components, for the maintenance of the living states and for the auto-cooperative transitions between the resting and active (or dead) living state. Having completed the theoretical section, the review goes on to describe the experimental testing of the theory carried out in the past forty-some years (and even in time before that by authors who knew nothing of the theory.) These experimental studies fall into two broad categories. In the first category, are the experiments performed on ultra-simple models of nano-protoplasm made up from pure chemicals as prescribed in Equation 1 on p. 124. The results show that they indeed behave qualitatively like that illustrated in Figure 5 and quantitatively follow the dictates of Equation 5. In the second category of experimental testing, parallel studies were carried out on nano-protoplasm as part of living cells--in carrying out each one of the four classical functions of cell physiology: (1) solute and water distribution; (2) solute and water permeability; (3) cellular resting and action potentials; (4) cellular swelling and shrinkage. The results show that the nano-protoplasm in situ too qualitatively behave like that shown in Figure 5 and quantitatively follow the dictates of Equation 5. The review ends on a discussion section, examining how cogent do the experimental data accumulated thus far support to the AI version of the concept of nano-protoplasm as the most basic unit of life.
Topics: Algorithms; Biology; Cells; Cytoplasm; History, 19th Century; History, 20th Century; Life; Models, Biological; Models, Chemical
PubMed: 19256352
DOI: No ID Found -
Annual Review of Physiology 1964
Review
Topics: Adenosine Triphosphate; Animals; Anura; Calcium; Cytoplasm; Cytoplasmic Granules; Electrons; Electrophysiology; Metabolism; Microscopy; Microscopy, Electron; Muscle Proteins; Muscles; Pharmacology; Physiology; Research
PubMed: 14145317
DOI: 10.1146/annurev.ph.26.030164.001023 -
Annual Review of Physiology 1950
Topics: Cells; Cytoplasm; Osmosis; Permeability
PubMed: 15411160
DOI: 10.1146/annurev.ph.12.030150.000255 -
Annual Review of Physiology 1948
Topics: Cytoplasm
PubMed: 18907245
DOI: 10.1146/annurev.ph.10.030148.000245 -
Science (New York, N.Y.) Feb 1974The protoplasmic viscosity was studied by using a small spin label having high permeability and broad solubility properties and nickel chloride as an extracellular...
The protoplasmic viscosity was studied by using a small spin label having high permeability and broad solubility properties and nickel chloride as an extracellular spin-subtracting agent to localize signal inside cells. The viscosity is variable and in some cells is many times that of water or phospholipids, suggesting that lateral diffusion in biological membranes is important to cell function.
Topics: Chlamydomonas; Cytoplasm; Electron Spin Resonance Spectroscopy; Escherichia coli; Humans; Lung; Nickel; Plant Cells; Pseudomonas; Saccharomyces cerevisiae; Spin Labels; Viscosity
PubMed: 4359084
DOI: 10.1126/science.183.4125.666 -
Annual Review of Physiology 1952
Topics: Cells; Cytoplasm
PubMed: 12977142
DOI: 10.1146/annurev.ph.14.030152.000305 -
Journal of Cellular and Comparative... Feb 1947
Topics: Cations; Cytoplasm; Ions; Muscles
PubMed: 20285919
DOI: 10.1002/jcp.1030290103 -
The Anatomical Record. Part A,... Dec 2005
Topics: Anatomy; Cytoplasm; History, 20th Century; Microscopy, Electron, Transmission; United States
PubMed: 16552845
DOI: No ID Found -
Cell May 2016Over a century ago, colloidal phase separation of matter into non-membranous bodies was recognized as a fundamental organizing principal of cell "protoplasm." Recent... (Review)
Review
Over a century ago, colloidal phase separation of matter into non-membranous bodies was recognized as a fundamental organizing principal of cell "protoplasm." Recent insights into the molecular properties of such phase-separated bodies present challenges to our understanding of cellular protein interaction networks, as well as opportunities for interpreting and understanding of native and pathological genetic and molecular interactions. Here, we briefly review examples of and discuss physical principles of phase-separated cellular bodies and then reflect on how knowledge of these principles may direct future research on their functions.
Topics: Animals; Colloids; Cytoplasm; Dequalinium; Humans; Organelles; Protein Interaction Mapping; Proteins
PubMed: 27203111
DOI: 10.1016/j.cell.2016.05.026