0515 Here is a list of benefits for subagents, including a cell-surface receptor and the contractile vacuole in paramecium.

0516 Surely, this list serves as criteria for models of the specificative and exemplar sign-interpretants (SI_s and SI_e).

0517 Section 10.4 discusses how subagents find ways to guide one another.  The configuration of a stimulus response comes to mind, where one sub-agent provides a signal_2a (a real-initiating event_2a) that provides information_2b for another subagent.

This is precisely what happens in the recent example.

0518 Indeed, I might imagine that a feedback loop might be established where the contractile vacuole, in its goal (SO_e), signals to the cell-surface agent (SV_s) to become less sensitive to nicotine.

0519 Is that how addiction works?

An ingested chemical that seems to meet a goal, for certain subagents, at first, later becomes less and less effective in meeting that goal, because of downregulation of sensitivity.

0520 Who knows?

The author spends a good deal of effort on discussing how viruses may trick subagents, just like one subagent may trick another, but not for long.  There are as many avenues to death as there are subagents.  The lesson is sobering.

0521 So, consider the following figure.

What is that dotted line?

The goal of the cell-surface sub-agent (SO_e) is to somehow send a message to the contractile vacuole (SV_s).

The dotted line is that inter-action.

0522 What is to prevent the cell-surface subagent from continually activating the contractile vacuole?

Well, death by exhaustion from continual spasms is one option.

The other option is that the contractile vacuole secretes something that alters the sensitivity of that particular cell-surface sub-agent.  If it so happens that the secretion also lowers the sensitivity of all cell-surface sub-agents, then that is a danger that the paramecium will have to… um… live with.

0523 That brings me back to the water fountain business.

One never quite knows whether signaling systems, once established, can morph into absolutely hilarious moments that appear to reduce productivity.

0524 So, my boss, the macronuclear type, waits for the right opportunity to establish a feedback system.

But, because everyone uses the water fountain, there only seems to be impediments.