# s-ecol: asymmetric cooperation during symbiosis (among Polynucleobacteria)

<< Relationships where two organisms depend on each other, known as symbiosis, evoke images of partnership and cooperation. But a new study in Nature Ecology and Evolution shows that, when it comes to certain microorganisms, symbiotic partners are actually being held "hostage" >>

Hostage situation or harmony? Researchers rethink symbiosis. July 27, 2017

https://m.phys.org/news/2017-07-hostage-situation-harmony-rethink-symbiosis.html

Vittorio Boscaro, Martin Kolisko, et al.  Parallel genome reduction in symbionts descended from closely related free-living bacteria. Nature Ecology & Evolution 1, 1160–1167 (2017) doi: 10.1038/s41559-017-0237-0 Publ. July 21,  2017

https://www.nature.com/articles/s41559-017-0237-0

# s-brain: behaviour vs. gut e-coli: twenty minutes after

<< Twenty minutes after a meal, gut microbes produce proteins that can suppress food intake in animals >>

<<  (..) gut bacteria may help control when and how much we eat >>

<< The new evidence coexists with current models of appetite control, which involve hormones from the gut signalling to brain circuits when we're hungry or done eating. >>

http://www.eurekalert.org/pub_releases/2015-11/cp-gms111715.php

Jonathan Breton, Naouel Tennoune, et al.  Gut Commensal E. coli Proteins Activate Host Satiety Pathways following Nutrient-Induced Bacterial Growth. Cell Metabolism, 2015; DOI: 10.1016/j.cmet.2015.10.017

http://www.sciencedirect.com/science/article/pii/S1550413115005665

# gst: collective patterns generated by capillary surfers.

<< Millimeter-sized “surfers” can self-propel across a vibrating liquid surface, interacting with other surfers to create collective patterns. >>

<< Self-propelled objects can move in mesmerizing patterns. The collective movements of groups of such objects typically occur in one of two flow regimes: the inertial regime—think swirling schools of fish in water—or the viscous regime—think swarming colonies of bacteria in mucus. Some self-propelled objects can travel in both flow regimes, a possibility that is less explored. >>️

AA << have studied the motion of a new system of self-propelled objects that move in this intermediate regime, finding that the objects organize into several distinct and tunable motion patterns. >>️️

<< Pairs of self-propelled surfers observed by the team move in one of seven different patterns (the video shows five). These include the “orbit,” where a pair of surfers rotate around a central point; the “tailgate,” where one surfer closely follows another, head to tail in a linear path; and the “jackknife,” where a pair of perpendicular surfers rotate stern to stern around their collision point. >>

<< When only one surfer was present, these mismatched amplitudes propelled the surfer in the direction of its bow. When there were two surfers close to each other, interactions among the waves caused the surfers to either repel each other so that they moved in opposite directions or to come together so that they collectively traced one of seven distinct patterns. >>️

️

Maggie Hudson. Synchronized Surfing of Self-Propelled Particles. Physics 16, s156. Nov 7, 2023. 

https://physics.aps.org/articles/v16/s156

Ian Ho, Giuseppe Pucci, Anand U. Oza, Daniel M. Harris. Capillary surfers: Wave-driven particles at a vibrating fluid interface. Phys. Rev. Fluids 8, L112001. Nov 7, 2023.

https://link.aps.org/doi/10.1103/PhysRevFluids.8.L112001

Anand U. Oza, Giuseppe Pucci, Ian Ho, Daniel M. Harris. Theoretical modeling of capillary surfer interactions on a vibrating fluid bath. Phys. Rev. Fluids 8, 114001. Nov 7, 2023.

https://link.aps.org/doi/10.1103/PhysRevFluids.8.114001

Also: waves, particle, swarm, in: https://www.inkgmr.net/kwrds.html

Keywords: gst, waves, wave-wave, capillary waves, particles, self-propelled particles, fluid-particle interactions, wave-particle interactions

# gst: ab.normal (fuzzy, bizarre) Nature; apparently, ancient bacterial parasites could have used CRISPR to self-defense and 'interference' for Ma ...

<< In recent years, the development of CRISPR technologies and gene-editing scissors in particular have taken the world by storm. Indeed, scientists have learned how to harness these clever natural systems in the biotech and pharmaceutical industries, among other areas. >>

<< New research (..) shows that we are not the first to find a way to exploit the benefits of the CRISPR technique. Apparently, primitive bacterial parasites have been doing so for millions of years. >>

<< Until recently, CRISPR-Cas was believed to be a defense system used by bacteria to protect themselves against invading parasites such as viruses, much like our very own immune system protects us. However, it appears that CRISPR is a tool that can be used for different purposes by diverse biological entities, (..) Here we found evidence that certain plasmids use type IV CRISPR-Cas systems to fight other plasmids competing over the same bacterial host. >> Rafael Pinilla-Redondo.

Humans are not the first to repurpose CRISPR. University of Copenhagen. Mar 24, 2020.

https://phys.org/news/2020-03-humans-repurpose-crispr.html

Rafael Pinilla-Redondo, David Mayo-Muñoz, et al. Type IV CRISPR–Cas systems are highly diverse and involved in competition between plasmids.  Nucleic Acids Research, Vol. 48, Issue 4, Pages 2000–12. doi: 10.1093/nar/gkz1197. Dec 27, 2019.

https://academic.oup.com/nar/article/48/4/2000/5687823

Also

keyword 'CRISPR' (Clustered Regularly Interspaced Short Palindromic Repeat) in PubMed:

 "CRISPR"[all] AND (Review[ptyp]) AND ("last 3 years"[PDat])

https://www.ncbi.nlm.nih.gov/pubmed/

keyword 'CRISPR' in FonT:

https://flashontrack.blogspot.com/search?q=crispr

keyword 'interferenza' | 'interferente' in Notes (quasi-stochastic poetry):

https://inkpi.blogspot.com/search?q=interferenza

https://inkpi.blogspot.com/search?q=interferente