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 :) > > 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. 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