Question on behavior of ciliates

About the shape and function of different specimens
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smollerthings
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Question on behavior of ciliates

#1 Post by smollerthings » Sat Oct 16, 2021 7:32 pm

I was thinking. Let's take the example of a stentor. When something dangerous arises, it contrasts itself. How does it do it without a central nervous system? Without a neural network to take the decision. Without the nerves to send the information to the contractile tissues. Do unicellular organisms have the equivalent of those in organelle version? :?

Dubious
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Re: Question on behavior of ciliates

#2 Post by Dubious » Sat Oct 16, 2021 9:35 pm

A fascinating subject. While single celled organisms like the Stentor lack a central nervous system, they obviously do have a "nervous system" of sorts that allows them to sense and react to physical stimulus. The Stentor is a good example of microbe "intelligence," with its surprisingly complex avoidance strategies--bending away from threats, retracting, and if nothing else works, breaking off from its stalk and swimming to a safer location. You should read the paper linked to below, reporting a study that vindicates Jennings' century old observations of the Stentor's hierarchy of avoidance behaviors. Most likely, as the paper suggests, it's all mechanical, but there are unanswered questions. The most likely candidates for the Stentor's "nervous system" are apparently its ciliate membrane and cytoskeletal cortex:

"The ciliate membrane and cytoskeletal cortex are the most likely candidates for mechanistically implementing the behaviors observed here. They underlie each of the individual behaviors shown in Figure 1C. The ciliate membrane is excitable. It harbors voltage-dependent and mechanosensitive ion channels that generate action potentials, analogous to those in neurons, and these channels play a key role in habituation [3]."

https://www.sciencedirect.com/science/a ... 14319#app2

smollerthings
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Re: Question on behavior of ciliates

#3 Post by smollerthings » Sun Oct 17, 2021 8:09 am

Incredible article. Thanks.
The cortex can propagate to daughter cells, in a non-genetic and Lamarckian manner, micro-surgical alterations to ciliary geometry, giving rise thereby to ‘‘cortical inheritance’’ [27].
That is the quote that really blew my mind. Transmission of acquired behaviors. Woooo

I mean, I always knew some behaviors are coded into the genome, one has only to look at cute baby animals to realize that these behaviors are innate and pre exist any learning opportunity. But I sort of assumed that it arose from a Darwinian style evolution. One can also argue that the language structure is largely innate (per Chomsky for ex.)

The propagation of the cortex to daughter cells as a direct Lamarkian propagation of bahaviors is very novel to me.

Hobbyst46
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Re: Question on behavior of ciliates

#4 Post by Hobbyst46 » Sun Oct 17, 2021 6:08 pm

smollerthings wrote:
Sun Oct 17, 2021 8:09 am
The cortex can propagate to daughter cells, in a non-genetic and Lamarckian manner, micro-surgical alterations to ciliary geometry, giving rise thereby to ‘‘cortical inheritance’’ [27].
...
That is the quote that really blew my mind. Transmission of acquired behaviors. Woooo
...
Out of curiosity, I tried to find that cited text, but failed. Had assumed that [27] in the quote signifies reference no. 27 in the article by Dexter et al., namely:

Beisson, J., and Sonneborn, T.M. (1965). Cytoplasmic inheritance of the organization of the cell cortex in Paramecium aurelia. Proc. Natl. Acad. Sci. USA 53, 275–282.

I downloaded the Beisson and Sonnenborn article and searched for the above citation in it - but in vain. Feeling very stupid. Where does it hide ?

smollerthings
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Re: Question on behavior of ciliates

#5 Post by smollerthings » Sun Oct 17, 2021 6:13 pm

Hobbyst46 wrote:
Sun Oct 17, 2021 6:08 pm
Out of curiosity, I tried to find that cited text, but failed. Had assumed that [27] in the quote signifies reference no. 27 in the article by Dexter et al., namely:
No, it is in the original publication sent by Dubious.

Hobbyst46
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Re: Question on behavior of ciliates

#6 Post by Hobbyst46 » Sun Oct 17, 2021 6:31 pm

smollerthings wrote:
Sun Oct 17, 2021 6:13 pm
Hobbyst46 wrote:
Sun Oct 17, 2021 6:08 pm
Out of curiosity, I tried to find that cited text, but failed. Had assumed that [27] in the quote signifies reference no. 27 in the article by Dexter et al., namely:
No, it is in the original publication sent by Dubious.
That is just what I do not understand. The original article apparently cites the Beisson article, which is no. 27 on his list. I could not find the "...Lamarckian..." sentence in the Beisson article. Oh well, just a small miss.

smollerthings
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Re: Question on behavior of ciliates

#7 Post by smollerthings » Sun Oct 17, 2021 6:50 pm

https://www.ncbi.nlm.nih.gov/pmc/articl ... 4-0051.pdf

Maybe it was extrapolated from the information?
Summary.--Pieces of cortex of Paramecium can be grafted onto a whole cell and become integrated, yielding a modified cortical pattern which is maintained through both sexual and asexual reproduction. Two types of modified cortical patterns were studied: presence of some rows of cortical units with reversed polarities and presence or absence of whole fields of rows of cortical units. An analysis of the development and maintenance of the modified patterns shows that, both at the level of fields of rows and at the level of the cortical unit, the organization (presence,location, orientation, and shape) of newly formed structures is determined by the cortical environment existing at the time of their development.

Dubious
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Re: Question on behavior of ciliates

#8 Post by Dubious » Sun Oct 17, 2021 7:16 pm

If the article link above does not work for you, try this link to a pdf of the article:

https://ars.els-cdn.com/content/image/1 ... 9-mmc3.pdf

Yes, shades of Lamarckism, Indeed. Through cortical inheritance, Stentor and similar ciliates just may have a means of passing on useful "learned" skills that is vastly more efficient than anything possessed by most of the higher orders of multi-celled creatures. To be able to pass skills learned in one generation on to the next, "higher" animals with true central nervous systems generally need to be living in a community where individuals recognize a new skill acquired and teach it to the next generation, and even with great apes and humans that has been a haphazard and uncertain affair.

DonSchaeffer
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Re: Question on behavior of ciliates

#9 Post by DonSchaeffer » Tue Nov 30, 2021 11:54 pm

Are you saying they inherit acquired behavior?

Dubious
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Re: Question on behavior of ciliates

#10 Post by Dubious » Wed Dec 01, 2021 1:48 am

DonSchaeffer wrote:
Tue Nov 30, 2021 11:54 pm
Are you saying they inherit acquired behavior?
Of a sort, bearing in mind that here any "learning" likely involves some kind of structural change. It is probably related to the Stentor's impressive regenerative ability, which utilizes molecular mechanisms that are still not understood:

"Stentor can regenerate following a vast range of surgical perturbations (Tartar, 1961), but despite over a century of experimental work on Stentor regeneration, we still know virtually nothing about how this cell regenerates at a molecular mechanistic level. "

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8511388/

smollerthings
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Re: Question on behavior of ciliates

#11 Post by smollerthings » Wed Dec 01, 2021 11:11 am

Dubious wrote:
Wed Dec 01, 2021 1:48 am
Of a sort, bearing in mind that here any "learning" likely involves some kind of structural change.
I think they were talking about behavior changes?

Dubious
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Re: Question on behavior of ciliates

#12 Post by Dubious » Wed Dec 01, 2021 5:50 pm

Yes, behavioral changes in response to external stimuli, Jennings observations fully vindicated, but more:

"In 1906, Herbert Spencer Jennings [14, 15] described in the sessile ciliate Stentor roeseli a hierarchy of responses to repeated stimulation, which are among the most complex behaviors reported for a singly nucleated cell [16, 17]... Our work resurrects Jennings’ pioneering insights and adds to the list of exceptional features, including regeneration [24], genome rearrangement [25], codon reassignment [26], and cortical inheritance [27], for which the ciliate clade is renowned."

https://vcp.med.harvard.edu/papers/jg-stentor+SI.pdf

Per the above articles, experimentation with Stentor's regenerative abilities reveals that biological information resides not just in the genome but is spread throughout molecular structures in other parts of the organism. While this results in Stentor's ability to rebuild itself almost from scratch, that together with cortical inheritance also apparently means that to some degree a Stentor can pass on "learned" information.

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