Returning all the bird books from a few weeks back.
Author: Chris Aldrich
I'm a biomedical and electrical engineer with interests in information theory, complexity, evolution, genetics, signal processing, IndieWeb, theoretical mathematics, and big history.
I'm also a talent manager-producer-publisher in the entertainment industry with expertise in representation, distribution, finance, production, content delivery, and new media.
Upstairs bathroom toilet fixed. The part fits and works like a charm.
Got the last toilet ball Ganahl Lumber had in stock. I’m hoping it’s the right size/length, but looks good. Cheaper than I thought it’d be.
Looking for toilet repair parts.
Looking to pick up a toilet part. Somehow they’re closed today, but open tomorrow?! Alas…
It’s been so long since I’ve driven anywhere in it, I had to stop in and wash the windshield to see where I was going. The tank is nearly full, so no gas today. Just a pandemic window wash please.
The potential for self-replication makes RNA an attractive candidate as a primordial catalysis in the origin of life. Catalysis may have occurred in some kind of compartment, possibly a fatty acid vesicle. However, RNA catalysis generally requires high levels of magnesium, which are incompatible with fatty acid vesicle integrity. Adamala and Szostak (p. [1098][1]) screened magnesium chelators and found that several—including citrate, isocitrate, and oxalate—could maintain the membrane stability of fatty acid vesicles in the presence of Mg2+. Citrate also allowed Mg2+-dependent RNA synthesis within protocell-like vesicles, while at the same time protecting RNA from Mg2+-catalyzed degradation. Efforts to recreate a prebiotically plausible protocell, in which RNA replication occurs within a fatty acid vesicle, have been stalled by the destabilizing effect of Mg2+ on fatty acid membranes. Here we report that the presence of citrate protects fatty acid membranes from the disruptive effects of high Mg2+ ion concentrations while allowing RNA copying to proceed, while also protecting single-stranded RNA from Mg2+-catalyzed degradation. This combination of properties has allowed us to demonstrate the chemical copying of RNA templates inside fatty acid vesicles, which in turn allows for an increase in copying efficiency by bathing the vesicles in a continuously refreshed solution of activated nucleotides. [1]: /lookup/doi/10.1126/science.1241888
Edited by Eörs Szathmáry
Volume 381, Pages 1-60 (21 September 2015)
With his chemoton theory theoretical biologist and chemical engineer Tibor Gánti was one of the most outstanding intellects behind systems chemistry a…
Analysis of the vocabulary of 123 tabulated definitions of life reveals nine groups of defining terms (definientia) of which the groups (self-)reproduction and evolution (variation) appear as the minimal set for a concise and inclusive definition: Life is self-reproduction with variations.
https://doi.org/10.1080/073911011010524992
Pages 71-96 | Published online: 15 Apr 2008
https://doi.org/10.1080/01969727108545830
Proto-organisms probably were randomly aggregated nets of chemical reactions. The hypothesis that contemporary organisms are also randomly constructed molecular automata is examined by modeling the gene as a binary (on-off) device and studying the behavior of large, randomly constructed nets of these binary “genes.” The results suggest that, if each “gene” is directly affected by two or three other “genes,” then such random nets: behave with great order and stability; undergo behavior cycles whose length predicts cell replication time as a function of the number of genes per cell; possess different modes of behavior whose number per net predicts roughly the number of cell types in an organism as a function of its number of genes; and under the stimulus of noise are capable of differentiating directly from any mode of behavior to at most a few other modes of behavior. Cellular differentiation is modeled as a Markov chain among the modes of behavior of a genetic net. The possibility of a general theory of metabolic behavior is suggested. Analytic approaches to the behavior of switching nets are discussed in Appendix 1, and some implications of the results for the origin of self replicating macromolecular systems is discussed in Appendix 6.
What is life and how could it originate? This question lies at the core of understanding the cell as the smallest living unit. Although we are witnessing a golden era of the life sciences, we are ironically still far from giving a convincing answer to this question. In this short article, I argue why synthetic biology in conjunction with the quantitative sciences may provide us with new concepts and tools to address it.
Gánti׳s chemoton model of the minimal chemical organization of living systems and life criteria for the living state and a living world are characteri…
The self-reproduction of supramolecular assemblies based on the synthesis and self-assembly of building blocks is a critical step towards the construction of chemical systems with autonomous, adaptive, and propagation properties. In this report, we demonstrate that giant vesicles can grow and produce daughter vesicles by synthesizing and incorporating phospholipids in situ from ad-hoc precursors. Our model involves acyl chain elongation via copper(I)-catalyzed azide-alkyne [3 + 2] cycloaddition reaction and the ensuing production of synthetic phospholipids to induce budding and division. In addition, the growth and budding of giant vesicles were compatible with the encapsulation and transfer of macromolecules as large as lambda phage DNA to the buds. This chemical system provides a useful model towards the implementation of cell-like compartments capable of propagation and transport of biological materials.