Collective behaviours: from biochemical kinetics to electronic circuits

In this work we aim to highlight a close analogy between cooperative behaviors in chemical kinetics and cybernetics; this is realized by using a common language for their description, that is mean-field statistical mechanics. First, we perform a one-to-one mapping between paradigmatic behaviors in chemical kinetics (i.e., non-cooperative, cooperative, ultra-sensitive, anti-cooperative) and in mean-field statistical mechanics (i.e., paramagnetic, high and low temperature ferromagnetic, anti-ferromagnetic). Interestingly, the statistical mechanics approach allows a unified, broad theory for all scenarios and, in particular, Michaelis-Menten, Hill and Adair equations are consistently recovered. This framework is then tested against experimental biological data with an overall excellent agreement. One step forward, we consistently read the whole mapping from a cybernetic perspective, highlighting deep structural analogies between the above-mentioned kinetics and fundamental bricks in electronics (i.e. operational amplifiers, flashes, flip-flops), so to build a clear bridge linking biochemical kinetics and cybernetics.Comment: 15 pages, 6 figures; to appear on Scientific Reports: Nature Publishing Grou

Mathematics and biology: a Kantian view on the history of pattern formation theory

Driesch’s statement, made around 1900, that the physics and chemistry of his day were unable to explain self-regulation during embryogenesis was correct and could be extended until the year 1972. The emergence of theories of self-organisation required progress in several areas including chemistry, physics, computing and cybernetics. Two parallel lines of development can be distinguished which both culminated in the early 1970s. Firstly, physicochemical theories of self-organisation arose from theoretical (Lotka 1910–1920) and experimental work (Bray 1920; Belousov 1951) on chemical oscillations. However, this research area gained broader acceptance only after thermodynamics was extended to systems far from equilibrium (1922–1967) and the mechanism of the prime example for a chemical oscillator, the Belousov–Zhabotinski reaction, was deciphered in the early 1970s. Secondly, biological theories of self-organisation were rooted in the intellectual environment of artificial intelligence and cybernetics. Turing wrote his The chemical basis of morphogenesis (1952) after working on the construction of one of the first electronic computers. Likewise, Gierer and Meinhardt’s theory of local activation and lateral inhibition (1972) was influenced by ideas from cybernetics. The Gierer–Meinhardt theory provided an explanation for the first time of both spontaneous formation of spatial order and of self-regulation that proved to be extremely successful in elucidating a wide range of patterning processes. With the advent of developmental genetics in the 1980s, detailed molecular and functional data became available for complex developmental processes, allowing a new generation of data-driven theoretical approaches. Three examples of such approaches will be discussed. The successes and limitations of mathematical pattern formation theory throughout its history suggest a picture of the organism, which has structural similarity to views of the organic world held by the philosopher Immanuel Kant at the end of the eighteenth century

Understanding the Biology of Clover Root Curculio and Improving Their Management Using Biofumigation in Alfalfa

Clover root curculio (CRC) is a pest of alfalfa where larvae feed belowground damaging alfalfa roots. Regional knowledge of CRC activity and biology is limited making the development of pest management strategies difficult. One potential management technique for soil-dwelling pests is the use of biofumigant containing cover crops. Biofumigation can affect the survival and behavior of pest insects. However, biofumigant crops have not been evaluated against CRC or as a rotational crop compatible with alfalfa. The goals of this research were to determine 1) phenology, population sizes, and root damage severity of CRC occurring in the Intermountain region and 2) the direct and indirect suppressive effects of biofumigant cover crop incorporations on CRC and its agronomic compatibility in rotation with alfalfa. First, I observed that larval activity occurred from mid-spring to mid-summer and local larval densities were generally lower than those reported in the eastern U.S. Adult CRC began emerging from the soil in mid-summer having two population peaks. After the second fall peak of adults was when most eggs were deposited which continued through early winter. CRC damage to taproots was cumulative, increasing as stands age, with most damage occurring in the first few years of stand life and mostly occurring in the top 20 cm of roots. While the incorporation of biofumigant crops appeared to be compatible with alfalfa and did not negatively affect yield, in field trials, biofumigation did not suppress CRC, disrupt egg laying, or decrease feeding damage. In one greenhouse trial, biofumigants significantly suppressed adult feeding rates more than non-biofumigant plants but the effect was not consistent. Biofumigant incorporation timing, for field trials in particular, may have contributed to the lack of CRC suppression. Overall, my research provides a better understanding of CRC phenology and activity in northern Utah and will assist in improving the timing of management approaches in alfalfa