Month: September 2022

RANGE OF MEASURES. "Different defense mechanisms are geared to fight different threats. Immunity systems might be highly effective against certain threats but less proficient against others. Suicide can serve as a defense mechanism that acts on those threats against which the immunity systems are less effective." https://lnkd.in/d9zsv9R View in LinkedIn

PRE-REQUISITES. "Population structure is required for the evolution of suicide. This pre-requisite had been previously proposed on the basis of experimental studies with a genetically engineered, suicidal strain of E. coli grown on agar plates and is theoretically extended here to a broader spectrum of population structures, suicide efficacies and co-occurring immune mechanisms." https://lnkd.in/d9zsv9R View in LinkedIn

SOCIAL POPULATIONS. "The presence of programmed cell death systems in the great majority of prokaryotes strongly suggests that structured populations are the rule in microbial ecosystems. Indeed, some kind of social interaction, such as biofilm formation, is found on almost every bacterial group, and more advanced forms of sociality, such as quorum sensing, are often present in Proteobacteria and Firmicutes." https://lnkd.in/d9zsv9R View in LinkedIn

RULES FOR DEVELOPMENT. "Evolution of suicide as a defense mechanism is only possible if (i) the host population is structured and (ii) the degree of immunity that the hosts can achieve by other means is limited. The widespread nature of suicide systems in prokaryotic genomes calls for a reconsideration of the relative importance of population structure for genome evolution." https://lnkd.in/d9zsv9R View in LinkedIn

FINAL NOTE. "Perhaps somewhat paradoxically, fixation of a costly adaptive immunity system is precluded not only when the innate immunity and suicide systems are highly effective but also when adaptive immunity itself performs at a high level. In such a case, hosts with and without adaptive immunity coexist in an environment where the pathogen is scarce (herd immunity effect)." https://lnkd.in/d9zsv9R View in LinkedIn

SO ENDS this contemplation of the relationship between pathogens and their hosts, and the balancing act between pathogen virulence and reproductive dispersal versus the evasive measures of the host including increased immunity and suicide, which reduce pathogen dispersal. This dance has gone on in parasite-host relationships in some form forever. At some level, the populations of both host and parasite have a meta-awareness of fecundity and costs, and these are brought to bear on the individual. An intriguing dance that reveals a lot about Nature. View in LinkedIn

VIRTUAL CREATURES. "Even this simple world is complex enough to require three different modes of interrogation: what it is (the material); what it does (the operational); and what it means (the symbolic). Feedback loops connect the material, operational, and symbolic into an integrated, recursively structured hierarchy." https://lnkd.in/dWchfhd View in LinkedIn

VIRTUAL CREATURES. "At the bottom of the hierarchy are electronic polarities, where the material and operational join to create bits, the semiotic markers of one and zero. Logic gates structure signals into bits; compiler languages are built out of bit patterns; programming languages are created from compiler languages." https://lnkd.in/dWchfhd View in LinkedIn

SYNTHETIC LIFE. "Scientists in the US have succeeded in developing the first living cell to be controlled entirely by synthetic DNA. The researchers constructed a bacterium's "genetic software" and transplanted it into a host cell." https://lnkd.in/dHrNzFp View in LinkedIn

FREE SPIRITS. "The work...of Sims (1994) and many others, has demonstrated the power of random variations selection to rapidly create autonomous entities with the potential to evolve out from under the control of their creators." https://lnkd.in/da2m8CW View in LinkedIn