On Sat, Apr 26, 2014 at 8:07 AM, Bruno Marchal <[email protected]> wrote:
> > On 25 Apr 2014, at 10:13, Telmo Menezes wrote: > > > > > On Fri, Apr 25, 2014 at 9:26 AM, Alberto G. Corona <[email protected]>wrote: > >> Just to contain the enthusiasm within rational levels: >> >> There is no comunism neither comunitarism at all. It is a fight >> between groups of clones that try to exploit one another (see below). >> The clones are comunists (because are clones, like the social >> insects). >> > > Even the analogy between social insects and communism seems flawed to me, > because social insects operate without central control. A find communism > more akin to how humans design machines. Social insects are > anarco-syndicalists, maybe :) > > > OK, social insects can have central control, although most using swarm > approach to AI might argue the contrary, > I confess that my limited knowledge of social insects comes from an interest in swarm AI. > but I don't think we can say that for the "social amoebas", which are > hardly "social" in the insect way. > I didn't expect my casual remark to be taken so seriously though (this is > not a serious remark either). > Does "this is not a serious remark either" apply to itself? :) Telmo. > > Bruno > > > > > > >> >> However the phenomenon is fascinating. >> >> >> From http://www.nature.com/nature/journal/v408/n6815/abs/408965a0.html >> >> ...If aggregating cells come from multiple clones, there should be >> selection for clones to exploit other clones by contributing less than >> their proportional share to the sterile stalk. Here we use >> microsatellite markers to show that different clones collected from a >> field population readily mix to form chimaeras. Half of the chimaeric >> mixtures show a clear cheater and victim. Thus, unlike the clonal and >> highly cooperative development of most multicellular organisms, the >> development of D. discoideum is partly competitive, with conflicts of >> interests among cells. These conflicts complicate the use of D. >> discoideum as a model for some aspects of development, but they make >> it highly attractive as a model system for social evolution. >> >> 2014-04-25 9:10 GMT+02:00, Bruno Marchal <[email protected]>: >> > >> > On 25 Apr 2014, at 07:39, Samiya Illias wrote: >> > >> >> Does scientific research back the claims made in this article? >> > >> > >> > Yes. Social amoeba are unicellular (capitalist) in good time, and >> > become communist in hard time. May be we should learn from them. >> > >> > I say yes but there are some details which I have not the time to >> > verify, of course. Notably the elimination of the cheater mutant. That >> > is quite plausible though. The Dictyostelium discoideum is a quite >> > fascinating organism, or should we say colony of organisms? >> > The communication means here are still very rudimentary, though, and I >> > don't think there are evidence for the "double word" communication >> > mentioned in the thread. >> > >> > Bruno >> > >> > >> > >> > >> >> Samiya >> >> >> >> Amoebic Morality <http://www.damninteresting.com/amoebic-morality/ > >> >> >> >> >> >> Dictyostelium discoideum composite photo, Copyright © M.J. Grimson & >> >> R.L. Blanton; Biological Sciences Electron Microscopy Laboratory, >> >> Texas Tech University >> >> Once food had been plentiful, but no longer. In the early days of >> >> the colony, the amoebas had feasted on a rich supply of bacteria. >> >> But as the generations passed and the population swelled, they had >> >> hunted out their food supply. Now starvation threatens. Their home-- >> >> a scrap of deer dung which once provided all their needs-- has >> >> become a trap which they must escape if they are to survive. At >> >> last, one amoeba sends out a cry for help. >> >> >> >> The starving amoeba begins to emit a chemical signal in the form of >> >> cyclic adenosine monophosphate, or cAMP. Nearby individuals sprout >> >> new pseudopods and crawl toward the source. They also begin to give >> >> off cAMP themselves, amplifying the call until the signal spreads to >> >> the far reaches of the colony. Amoebas cannot concurrently detect >> >> and produce cAMP, so they alternate, and the cells trace out >> >> intricate spiral patterns as they surge forward in waves. >> >> >> >> The amoebas pile on top of one another in growing numbers until so >> >> many of them have joined the heap that this pile of microscopic >> >> single-celled organisms becomes visible to the naked eye. At first >> >> their behavior might seem odd; to gather together in the face of >> >> starvation surely ought to end in cannibalism or death. Not so, for >> >> they are capable of an extraordinary and rare transformation. The >> >> amoebas set aside their lives as individuals and join ranks to form >> >> a new multicellular entity. Not all the amoebas will survive this >> >> cooperative venture, however. Some will sacrifice themselves to help >> >> the rest find a new life elsewhere. >> >> >> >> These astonishing creatures are Dictyostelium discoideum, and they >> >> are a member of the slime mold family. They are also known as social >> >> amoebas. Aside from the novelty value of an organism that alternates >> >> between unicellular and multicellular existence, D. discoideum is >> >> highly useful in several areas of research. Among other things, this >> >> organism offers a stellar opportunity to study cell communication, >> >> cell differentiation, and the evolution of altruism. >> >> >> >> In response to the cAMP distress call, up to one hundred thousand of >> >> the amoebas assemble. They first form a tower, which eventually >> >> topples over into an oblong blob about two millimeters long. The >> >> identical amoebas within this pseudoplasmodium-- or slug-- begin to >> >> differentiate and take on specialized roles. >> >> >> >> The slug begins to seek out light, leaving a slimy trail behind. >> >> Some of the amoebas take on the difficult role of sentinel, or >> >> immune-like functions. They circulate through the slug, hunting for >> >> pathogens. If they find any, they will engulf them in a process >> >> similar to the feeding behavior they once displayed when in solitary >> >> form. The pseudoplasmodium periodically sloughs off the sentinels-- >> >> and any pathogens they have engulfed-- and abandons them in the >> >> trail of slime. More cells will then be tapped to fill their place. >> >> >> >> >> >> >> >> Dictyostelium discoideum slug >> >> Once the slug finds a suitably sunny location, the unlucky cells at >> >> the "head" of the slug form a stalk for the others to climb. These >> >> cells--which make up roughly a fifth of the total population--will >> >> sacrifice themselves in order to provide a path up for their comrades. >> >> >> >> The remaining cells then climb the stalk and collect on its tip, >> >> eventually resulting in a structure resembling a ping-pong ball >> >> balanced on top of a floppy wire. This formation is known as a >> >> "fruiting body." They then form spores, which are carried away by >> >> wind or passing animals or insects. Once carried to a suitable >> >> location, the amoebas emerge from spore form and begin the cycle >> >> again. >> >> >> >> So long as all the amoebas which make up the slug are related, this >> >> impressive display of self-sacrifice on the part of the stalk cells >> >> makes sense. Though they will perish in the act of creating the >> >> stalk, they will pass along their genetic legacy via their kin. In >> >> fact, when the amoebas reproduce by division, they create an ever- >> >> increasing pool of genetically identical clones. These clones suffer >> >> no genetic cost at all from sacrificing their lives for each other. >> >> >> >> More familiar multicellular organisms pool resources in a similar >> >> way. For example, in a human being, a liver cell fills a very >> >> different role from a lung or skin cell, but all of them harbor the >> >> same chromosomes. The result is that the liver doesn't need to >> >> compete with the lungs concerning reproduction. So long as the germ >> >> cells get lucky, all of the cells can be (metaphorically) content >> >> knowing they will pass on their genetic legacy. >> >> >> >> However, when the cAMP call goes out, it isn't only related amoebas >> >> that answer it. Those of differing strains will come together to >> >> form a single slug. If one strain could figure out a way to duck out >> >> of stalk and sentinel duty, it would be expected to reproduce faster >> >> than its nobler compatriots. >> >> >> >> As is true with all organisms, some will evolve in such a way that >> >> they can-- and will-- benefit from the colony's resources without >> >> contributing anything back. In theory, such "leeches" could >> >> potentially have a survival and reproductive advantage, thereby >> >> undermining the cooperative Dictyostelid lifestyle. Such cheating >> >> does take place, but nonetheless D. discoideum has been around for >> >> millions of years with no signs of imminent extinction. Thus the >> >> mechanisms for keeping cheating under control must be effective. >> >> >> >> For one thing, the amoebas prefer to unite with kin. The amoebas are >> >> able to recognize each other through molecular markers. They mingle >> >> with other strains only when populations are low. At such times, the >> >> ability to form a larger slug outweighs the risk of cooperating with >> >> strangers. >> >> >> >> >> >> >> >> A typical amoeba >> >> In addition, evidence suggests that some social amoebas have evolved >> >> to link reproductive genes with altruistic ones. In the case of D. >> >> discoideum, researchers created a mutant strain of cells which are >> >> "deaf" to the chemical signal to become a self-sacrificing stalk >> >> cell. They then watched to see if these cells would gain a >> >> reproductive advantage. Just the opposite took place. The "cheater" >> >> mutant cells did not join in stalk formation, yet they rarely made >> >> it up the stalk to become spores, and therefore they died out. The >> >> traits of self-sacrifice and reproduction had become genetically >> >> entangled, it seems, allowing only the altruistic amoebas to produce >> >> offspring. >> >> >> >> Finally, opportunities for cheating simply aren't very common. In >> >> the wild, these creatures spend much of their lives reproducing via >> >> division, and surrounding themselves with identical copies. Outside >> >> of laboratory experiments, cases where social amoebas run across >> >> strangers to exploit are rare. Cheater genes peter out once the >> >> cheaters run out of nobler amoebas to sponge off of. When exploiting >> >> one's clone mates, greed doesn't pay. >> >> >> >> In addition to studies of altruism, study of D. discoideum is >> >> shedding light on how cells communicate. D. discoideum uses many of >> >> the same signaling processes found in all multicellular creatures. >> >> But unlike fish or frogs, D. discoideum can be frozen, thawed, grown >> >> by the millions in a matter of days, and stored away for years if >> >> need be. A website called DictyBase offers an impressive list of >> >> breakthroughs which can be credited to the social amoeba. >> >> >> >> The consistency with which these amoebas act in the common good >> >> might inspire admiration in many. Yet a more cynical observer might >> >> point out that the amoebas are moved not by love of family and >> >> friends, nor by moral scruples, but by the cold mechanics of natural >> >> selection. Amoebas behave altruistically only because natural >> >> selection has led to a stable state in which self-sacrifice is the >> >> best way for them to pass on their genes. But the end result is the >> >> same, regardless of the natural forces that have shaped it. Altruism >> >> triumphs, and through their mutual selflessness the amoebas arrive >> >> at a new patch of bacteria-laden dung to call home. >> >> >> >> Written by Carol Otte, posted on 09 October 2007. Carol is a >> >> contributing editor for DamnInteresting.com. >> >> >> >> >> >> >> >> On Thu, Apr 24, 2014 at 6:54 PM, Bruno Marchal <[email protected]> >> >> wrote: >> >> >> >> On 24 Apr 2014, at 12:26, Richard Ruquist wrote: >> >> >> >>> Microbes provide insights into evolution of human language >> >>> April 23rd, 2014 in Biology / Cell & Microbiology >> >>> >> >>> Gram-stained Pseudomonas aeruginosa bacteria (pink-red rods). >> >>> Credit: GFDL, CC-by-sa >> >>> >> >>> Big brains do not explain why only humans use sophisticated >> >>> language, according to researchers who have discovered that even a >> >>> species of pond life communicates by similar methods. >> >>> >> >>> Dr Thom Scott-Phillips of Durham University led research into >> >>> Pseudomonas aeruginosa, a type of bacteria common in water and >> >>> soil, which showed that they communicated in a way that was >> >>> previously thought to be unique to humans and perhaps some other >> >>> primates. >> >>> >> >>> The bacteria used combinatorial communication, in which two signals >> >>> are used together to achieve an effect that is different to the sum >> >>> of the effects of the component parts. This is common in human >> >>> language. For example, when we hear 'boathouse', we do not think of >> >>> boats and houses independently, but of something different - a >> >>> boathouse. >> >>> >> >>> This type of communication had never been observed in species other >> >>> than humans and some other primates, until colonies of Pseudomonas >> >>> aeruginosa were shown to be using the same technique - not, of >> >>> course, with spoken words but with chemical messengers sent to each >> >>> other that signalled when to produce certain proteins necessary for >> >>> the bacteria's survival. >> >>> >> >>> By blocking one signal, then the other, the researchers showed if >> >>> both signals were sent separately, the effect on protein production >> >>> was different from both signals being sent together. >> >>> >> >>> Dr Scott-Phillips, a research fellow in evolutionary anthropology >> >>> at Durham University, conducted the research in collaboration with >> >>> a team of experts in bacteriology from the universities of >> >>> Nottingham and Edinburgh. >> >>> >> >>> He commented: "We conducted an experiment on bacterial >> >>> communication, and found that they communicate in a way that was >> >>> previously thought to be unique to humans and perhaps some other >> >>> primates. >> >>> >> >>> "This has serious implications for our understanding of the origins >> >>> of human communication and language. In particular, it shows that >> >>> we can assume that combining signals together is unique to the >> >>> primate lineage." >> >>> >> >>> More information: 'Combinatorial communication in bacteria: >> >>> Implications for the origins of linguistic generativity', Scott- >> >>> Phillips et al, published in PLOS One, 23 April 2014. >> >>> www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0095929 >> >>> >> >>> Provided by Durham University >> >>> >> >>> "Microbes provide insights into evolution of human language." April >> >>> 23rd, 2014. >> >>> >> http://phys.org/news/2014-04-microbes-insights-evolution-human-language.html >> >> >> >> >> >> The contrary would have astonished me a lot, but it is nice this is >> >> confirmed and studied (I was sure it was). Comparison with language >> >> might be slightly stretched as there is no symbolic role in the >> >> messages, but may be it can make sense (I am not sure, I will read >> >> the paper ... but that does not seem really in his topics). I have >> >> few doubts that our own cells communicate in very sophisticate >> >> chemical ways, and there are evidences that plants does communicate >> >> through their roots, may be even through bacteria. (But no proof of >> >> such explicit double "words" nuancing, although again, its non >> >> existence would be astonishing). I would have bet this was already >> >> discovered on Escherichia Coli, but not in that apparently explicit >> >> way. >> >> Hmm... I'm not sure that they verified enough that the two compounds >> >> don't react to get a third molecule, which would trivialize the >> >> discovery. >> >> So interesting, but has to be continued and confirmed, ... >> >> >> >> Bruno >> >> >> >> >> >> >> >>> >> >>> -- >> >>> You received this message because you are subscribed to the Google >> >>> Groups "Everything List" group. >> >>> To unsubscribe from this group and stop receiving emails from it, >> >>> send an email to [email protected]. >> >>> To post to this group, send email to everything- >> >>> [email protected]. >> >>> Visit this group at http://groups.google.com/group/everything-list. >> >>> For more options, visit https://groups.google.com/d/optout. >> >> >> >> http://iridia.ulb.ac.be/~marchal/ >> >> >> >> >> >> >> >> >> >> -- >> >> You received this message because you are subscribed to the Google >> >> Groups "Everything List" group. >> >> To unsubscribe from this group and stop receiving emails from it, >> >> send an email to [email protected]. >> >> To post to this group, send email to [email protected]. >> >> Visit this group at http://groups.google.com/group/everything-list. >> >> For more options, visit https://groups.google.com/d/optout. >> >> >> >> >> >> -- >> >> You received this message because you are subscribed to the Google >> >> Groups "Everything List" group. >> >> To unsubscribe from this group and stop receiving emails from it, >> >> send an email to [email protected]. >> >> To post to this group, send email to [email protected]. >> >> Visit this group at http://groups.google.com/group/everything-list. >> >> For more options, visit https://groups.google.com/d/optout. >> > >> > http://iridia.ulb.ac.be/~marchal/ >> > >> > >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups >> > "Everything List" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> an >> > email to [email protected]. >> > To post to this group, send email to [email protected]. >> > Visit this group at http://groups.google.com/group/everything-list. >> > For more options, visit https://groups.google.com/d/optout. >> > >> >> >> -- >> Alberto. >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Everything List" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/everything-list. >> For more options, visit https://groups.google.com/d/optout. >> > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > > > http://iridia.ulb.ac.be/~marchal/ > > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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