A theoretical model is presented for early evolutionary cell sorting within cellular aggregates. The model involves an energy-saving mechanism and principles of collective self-organization analogous to those observed in bicycle pelotons (groups of cyclists). The theoretical framework is applied to slime-mold slugs (Dictyostelium discoideum) and incorporated into a computer simulation which demonstrates principally the sorting of cells between the anterior and posterior slug regions. The simulation relies on an existing simulation of bicycle peloton dynamics which is modified to incorporate a limited range of cell metabolic capacities among heterogeneous cells, along with a tunable energy-expenditure parameter, referred to as an “output-level” or “starvation-level” to reflect diminishing energetic supply. Proto-cellular dynamics are modeled for three output phases: “active”, “suffering”, and “dying or dead.” Adjusting the starvation parameter causes cell differentiation and sorting into sub-groups within the cellular aggregate. Tuning of the starvation parameter demonstrates how weak or expired cells shuffle backward within the cellular aggregate.

 

Cell pelotons: A model of early evolutionary cell sorting, with application to slime mold Dictyostelium discoideum

HughTrenchard

Journal of Theoretical Biology
Volume 469, 21 May 2019, Pages 75-95

Source: www.sciencedirect.com

Radically new dynamics in the early 20th century transformed cars and, in turn, the world. Here’s why the next great inflection point is upon us, auguring changes no less profound.

Source: www.mckinsey.com

Will the coming mobility revolution make urban traffic better, or worse?

Source: www.mckinsey.com

Our mental models about mobility—individually owned cars, gas stations, traffic jams, the driver’s license as a rite of passage—are on the verge of disruption. Mobility is about to become cheaper, more convenient, a better experience, safer, and cleaner—not 50 or even 25 years from now, but perhaps within a dozen.

We describe the coming transformation as mobility’s Second Great Inflection Point, because it has the potential to be as profound as the one that put horses to pasture and revolutionized industries and societies worldwide. A defining characteristic of the new world taking shape is that the automotive industry, which has operated for more than a century alongside but decidedly disconnected from other components of what transportation has come to mean, will blend into a more interconnected, customer-centric ecosystem. That shift boosts the odds that the momentous changes afoot will affect your business, even if the closest you currently get to a car is your morning commute.

Source: www.mckinsey.com

Systems chemistry deals with the design and study of complex chemical systems. However, such systems are often difficult to investigate experimentally. We provide an example of how theoretical and simulation-based studies can provide useful insights into the properties and dynamics of complex chemical systems, in particular of autocatalytic sets. We investigate the issue of the required molecular diversity for autocatalytic sets to exist in random polymer libraries. Given a fixed probability that an arbitrary polymer catalyzes the formation of other polymers, we calculate this required molecular diversity theoretically for two particular models of chemical reaction systems, and then verify these calculations by computer simulations. We also argue that these results could be relevant to an origin of life scenario proposed recently by Damer and Deamer.

 

Life 2019, 9(1), 23; https://doi.org/10.3390/life9010023
Molecular Diversity Required for the Formation of Autocatalytic Sets
Wim Hordijk, Mike Steel and Stuart A. Kauffman

Source: www.mdpi.com