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wrote...
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A year ago
This behaviour is known as chemotaxis. This article describes it well: The slime mold Physarum polycephalum is a unicellular, multinucleate protist that relies on reactive navigation to explore its environment. The vegetative state of P. polycephalum (known as a plasmodium) is composed of many smaller oscillating units. Each unit oscillates at a frequency dependent upon both the local environment and its interactions with neighboring oscillators (11). When the slime mold senses attractants, such as food, via specific binding to receptor molecules presented on the outer membrane surface (12), the oscillation frequency in the area closest to the food increases, causing cytoplasm to flow toward the attractant (13). Additionally, binding of attractant molecules to sections of the surface membrane reduces the tension at that section, leading to a difference in internal hydrostatic pressure, such that cytoplasm flows toward the source of attractants (12). When repellents such as salts and light are detected, oscillation frequency decreases and membrane tension increases (12). The collective behavior of the oscillators, each passing on information to entrain its neighbors, drives the organism’s locomotion. https://www.pnas.org/doi/10.1073/pnas.1215037109
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wrote...
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A year ago
Edited: A year ago, oemBiology
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"As it moves, the plasmodium leaves behind a thick mat of nonliving, translucent, extracellular slime (Fig. 1). This extracellular slime is a high molecular weight, polyanionic glycoprotein (14), consisting largely of sulfated galactose polymers (15). As the plasmodium is foraging, we found that it strongly avoids areas that contain extracellular slime.
This avoidance behavior is a “choice” because when no previously unexplored territory is available, the slime mold no longer avoids extracellular slime (see further). "
How do plasmodium handle extracellular slime for this choice as an avoidance behavior?
Slime mold seems not have intelligence, should decision making for this "choice" 99.99% based on chemical reaction?
Is there any related article talking about this issue?
Do you have any suggestions?
Thank you very much for any suggestions (^v^)
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wrote...
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A year ago
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Far questions to ask, because it nature makes you start to redefine intelligence.
When the slime mold forages, it leaves behind a translucent slime. The slime then tries avoiding this area as its indicative of areas where it has already traveled. This extracellular slime is a kind of externalized spatial memory that reminds polycephalum to explore somewhere new. Hence, it uses the slime it coats the area with as a map to navigate. BUT, if you were to pre-coat the area with slime, and then place the species into the area, it doesn't have the "intelligence" to know its slime from another species slime. Hence, to answer your question, slime molds make their decisions solely on chemical reactions.
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wrote...
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A year ago
Edited: A year ago, oemBiology
slime molds make their decisions solely on chemical reactions. That is very common in nature on managing signals for survival. Ants search for foods based chemical reaction as well. Is there any related articles talking about how slime mold / ants behavior differently based on different levels of chemical concentration? Such as chemical concentration for slime mold extracellular slime (100%) = avoidance behavior (100%) extracellular slime 80%) = avoidance behavior (? %) extracellular slime (60%) = avoidance behavior (? %) extracellular slime (40%) = avoidance behavior (? %) extracellular slime (20%) = avoidance behavior (? %) extracellular slime (0%) = avoidance behavior (0%) Do you have any suggestions? Thank you very much for any suggestions (^v^) On the other words, what kind of ion channel is being used by slime mold in order to trigger avoidance behavior? 1) Voltage-gated ion channel, only open when the membrane potential reaches a certain value 2) Ligand-gated ion channel, only open when they are bound by a specific molecule 3) Mechanically-gated ion channel, only open in response to physical forces, such as change in length or in pressure 4) Other
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wrote...
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A year ago
Edited: A year ago, oemBiology
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White blood cells can detect inflected area by chemical released from bacteria.
what kind of ion channel is being used by white blood cell in order to detect chemical released from bacteria?
I think this approach is very common in nature.
Do you find any related articles about this issues?
Thank you very much for any suggestions (^v^)
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wrote...
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A year ago
On the other words, what kind of ion channel is being used by slime mold in order to trigger avoidance behavior? 1) Voltage-gated ion channel, only open when the membrane potential reaches a certain value 2) Ligand-gated ion channel, only open when they are bound by a specific molecule 3) Mechanically-gated ion channel, only open in response to physical forces, such as change in length or in pressure 4) Other This is the article that addresses this question. I don't know the answer immediately because there aren't too many studies that have studied the pathway or physiology behind this avoidance behavior in slime. Other species, such as E. coli, researchers have studied more extensively. For example, E. coli release cAMP in response to stress, but of course that's bacteria, not fungi. https://royalsocietypublishing.org/doi/10.1098/rstb.2019.0470In the present study, we tested the hypotheses that: (i) slime moulds release chemical cues in the environment when facing various stressors, and (ii) these cues can be sensed and used adaptively by other slime moulds. To test our hypotheses, we manipulated the physiological conditions of slime moulds exploring an environment using biotic or abiotic stresses. We then recorded the behavioural response of slime moulds facing substrates explored by stressed or undisturbed clone mates. To date, to our knowledge, no studies have demonstrated that slime moulds convey information regarding stressful situations that can be sensed by conspecifics. Sensing clone mates' stress would allow slime moulds to rapidly escape conditions that limit their growth by orienting their movement towards a more favourable environment. Please have a read and get back to us!
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wrote...
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A year ago
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I read through most of statements, but I cannot find any description on how slime mold collects external chemical elements and convert into Action Potential in the Neuron before becoming action (avoidance behavior), this part of neuron process is very important on filtering data and making decision for Action Potential in the Neuron.
Do you find any more related articles about this issue?
Thank you very much for any suggestions (^v^)
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wrote...
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A year ago
Hi oemBiologyI found plenty of related information: In the cellular slime mould D. discoideum, cAMP is released extracellularly in response to nutritional stress and acts as a chemoattractant promoting aggregation Interestingly, in P. polycephalum, Kincaid & Mansour [65] found out that cAMP is repulsive at high concentration while being an effective chemoattractant at lower concentration. In both cellular and acellular slime moulds, caffeine affects the activation of cAMP synthesis and alters the distribution of intracellular calcium (it enhances calcium flux within the cell) Illumination with ultraviolet (UV) or blue light also increased cAMP levels [68] and causes drastic changes in the cytoplasmic calcium concentration, as observed with caffeine [69]. Based on this information, cAMP, if secreted extracellularly in high enough concentration by slime moulds stressed with either nutrient deprivation, light or toxin, could be used by their clone mates as a cue to avoid risky environments. Boussard et al. [70] have shown in P. polycephalum that when exploring a substrate containing salt (NaCl), slime moulds absorb and store the salt intracellularly. Then, when introduced in salt-free environment, these slime moulds release the salt extracellularly.
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wrote...
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A year ago
Edited: A year ago, oemBiology
Interestingly, in P. polycephalum, Kincaid & Mansour [65] found out that cAMP is repulsive at high concentration while being an effective chemo attractant at lower concentration. In both cellular and acellular slime moulds, caffeine affects the activation of cAMP synthesis and alters the distribution of intracellular calcium (it enhances calcium flux within the cell) I would like to confirm on whether Slime Mold use ion channel to collect chemical from external environment or not at the first place. If yes, then to trigger action for avoidance behavior, if it is based on chemical concentration, I would like to know on which kind of ion channel is being used to detect the concentration in order to trigger avoidance behavior, then I may know on how data is being handled by slime mold for action. 1) Voltage-gated ion channel, only open when the membrane potential reaches a certain value 2) Ligand-gated ion channel, only open when they are bound by a specific molecule 3) Mechanically-gated ion channel, only open in response to physical forces, such as change in length or in pressure 4) Other Do you have any suggestions? Thank you very much for any suggestions (^v^)
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wrote...
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A year ago
1) Voltage-gated ion channel, only open when the membrane potential reaches a certain value 2) Ligand-gated ion channel, only open when they are bound by a specific molecule 3) Mechanically-gated ion channel, only open in response to physical forces, such as change in length or in pressure 4) Other Sometimes cells communicate with the environment without any of these. For example, a ligand such as a glycoprotein released by the slime initially when it scavenges the area may interact with a protein later on, on its surface that eventually activate the cAMP signaling pathway downstream within the cell. The cAMP signaling pathway triggers the release or "enhances calcium flux within the cell". I'm not sure if the article goes into detail, as I did not read it in its entirety.
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wrote...
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A year ago
Edited: A year ago, oemBiology
If it is the case, then Slime Mold collects chemical from external environment, would they be used following approaches instead? Referring to following video, I would like to know on how different level of solute concentration affects their rates of diffusion. 1) Diffusion: movement of solute molecules from an area of higher concentration to an area of lower concentration 2) Osmosis Is the diffusion of solvent across a membrane, the movement solvent molecules from a region of lower solute concentration to a region of higher solute concentration. 3) Dialysis is the process of separating molecules in solution by the difference in their rates of diffusion through a semipermeable membrance. Do you find any related articles about this issue? Thank you very much for any suggestions (^v^) Is there any formula to determine the rate of diffusion based on different levels of concentration?  Do you have any suggestions? Thank you very much for any suggestions (^v^)
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wrote...
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A year ago
Edited: A year ago, oemBiology
Referring to following link, I would like to know on whether calculation is correct or not for calculating the rate of diffusion.  J = [D x A x (C1 - C2)] / L Case 1 (C1 - C2) = 10 C1 = 400 C2 = 390 Case 2 (C1 - C2) = 10 C1 = 40 C2 = 30 Would both cases be the same speed in term of rate of diffusion? Do you have any suggestions? Thank you very much for any suggestions (^v^)
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wrote...
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A year ago
Hi oemBiologySorry for the late response. Diffusion is the movement of solute from an area of high concentration to low concentration. Assume a container is separated by a membrane that's permeable to solute x. If one side is highly more concentrated that the other for the solute x, it will influence the speed of diffusion. Other factors include surface area, and that's summarized by Fick's law, which states that the rate of diffusion of a substance across unit area is proportional to the concentration gradient. If in J = [D x A x (C1 - C2)] / L, D,A and L remain constant, mathematically J will be the same.
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