Gravitation induced transformation of singular cells to simple

  • Gravitation induced transformation of singular cells to simple multicellularity

             Iresh Ranjan Bhattacharjee   

           July 7, 2016

    Ratcliff et al. (2012) claimed to carry out a novel experiment to evolve simple multicellularity in the lab, starting with single-celled microbes. Though the researchers admitted in their language that “We used gravity to select for primitive multicellularity in the unicellular yeast” but they did not elaborated the nature of gravity. As usual what most life scientists perceive gravity as something ‘weighty’ that spatially goes downward faster, dominated in the expression. The aforesaid researchers claimed “to create an environment that favored strains that evolve to form clusters of cells, as the first step in the transition to multicellularity, by subjecting Baker’s yeast (Saccharomyces cerevisiae) to daily selection for fast settling through liquid medium. Within just a few weeks, yeast, that formed snowflake-shaped clusters of cells, evolved and displaced their single-celled ancestors. “Snowflake” yeast display several hallmarks of multicellularity, including juvenile and adult life stages, determinate growth, and a rudimentary cellular division of labor utilizing programmed cell death.”

    Bhattacharjee (2013) had demonstrated that gravitational anchor is a criterion for manifestation as living. Proverb that “A Rolling stone gathers no moss" is not only a literary proverb but based on scientific observation and fact of the commoners. Biomass is initially to be anchored through inertia of the critical amount of callus/ explants, suspension of cultures, or cell density for a three dimensional cell to be pivoted on the central axis of the self gravity. Daily selection for fast settling through liquid medium and then formation of clusters of cells are thus the natural consequence of gravitation. We have already theorized that a single cell is difficult to survive under natural condition without being self-gravitationally anchored or attaining steady state condition or under multi-assembled single cell condition. A single cell cannot survive in isolated way, unless it is anchored by inertia. A minimal inertial mass is required for survival. In plant tissue culture, unless a callus (“explants”) of say above 500 mg or suspension of cultures of say, 3-4 cubic centimeter (in terms of PCV - packed cell volume) is used, it is difficult to maintain continuity of life and growth from individual cells. Similarly in the final volume for cell culture, maintaining cell density as low as 3 x 10^5 to high of more than 10–15x 10^6 cells/ ml of inoculums are required. Why a minimum mass is required for cell culture under multi-assembled single cell condition. It is for gravitational anchorage. Had the aforesaid worker observed meticulously, they would have noticed that there would be a central position, which as per theory of gravitation, as if entire mass in the sphere of influence of such gravitating system would have been concentrated at the center (Fig 1). This is a distinguishable features of gravitational force compared to other basic forces viz. electromagnetic forces or any other local forces like surface tension, elastic forces etc.

    Fig 1. Transformation of singular cells to simple multicellular. As per nature of gravitation, entire mass, as if, have been concentrated at the center, of the sphere of influence.

    In selection of genotype, the researcher would have got better insight had they worked out additionally the molar mass and the density of the clusters, as to them "clusters have greater fitness only with gravitational selection". As per astrophysical principle, where gravitation is explicitly dealt,  ‘higher the mass and density- higher would be the attractive force of self gravity’ or in reverse way ‘lesser would delay the attraction”. Molar weight and density based chronological movements of macromolecules viz. nucleic acid, proteins, fats and lipids are available in cell, that has been dealt elsewhere. Nucleic acid having higher molar mass and density remain in core position, protein being intermediate over fats and lipids get distributed away from core. In the matter of evolution, there is no need to bring alien seed from galaxy. With the data on molar mass and density, we could have get clear insight that genotypes are playing under a condition of "Repeat under same physics". To understand repeat under same physics, let us cite an imaginary example. Say, 10 runners are allowed to run in an athletic track. After some time, let us instruct all the runners to return, as is where basis, back to their original position of starting. At this moment of return instruction, runners are expected to line up  at different distances, say, 1,2,3,4, and so on positions, in accordance with their strength and performance. So when runners in different position return to their base point, all will return at the same time, irrespective of position 1,2,3,4. and so on, as seen in half-way. This is a paradox. So the subsequent advance study by the same group (Ratcliff, W. C. et al. 2015) would have given a complete picture had these are been supported with the information of parameters like molar weight and density affecting gravitational force in addition to genomic sequence. As genomic sequence has to repeat under same physics i.e. environment, as is demonstrated, in the example of issuing command to all runners to return to base point under same competitive performance. 

    References:

    Ratcliff, W. C., Denison, R. F., Borrello, M. & Travisano, M. Experimental evolution of multicellularity.  Natl Acad. Sci. USA109, 1595–1600 (2012).

    Bhattacharjee I.R. (2013) Self Gravity: The Major Investigation Gap in Life Science. Lambert Academic Publishing ISBN 978-3-659-42698-8.

    Ratcliff, W. C. et al. (2015) Origins of multicellular evolvability in snowflake yeast.Nat. Commun. 6:6102 doi: 10.1038/ncomms7102.

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