Cephalopod Arms

Damien

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very interesting. I will read it on my ebook reader.

Is there any data about comparison between arms and tentacules regeneration for a decapod ? ( except of course the size which should have an impact on regeneration's speed and energetic's cost)
 

DWhatley

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That would be difficult to document I think since squid do not do well in an aquarium small enough to observe them over a long (relatively speaking) period of time (looking back, this was one of the summary points I noted in the article as well). I know Robyn has done some work on "pain" in squid but don't know if they recorded any observed regeneration of arms.
 

Damien

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Ok, I see.

As usually, pelagic species not easily maintainables in aquarium(or not long enough) are always to difficult to study.
 

DWhatley

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Octopus arm regeneration: Role of acetylcholinesterase during morphological modification Sara Maria Fossati, Francesca Carella, Gionata De Vico, Fabio Benfenatia, Letizia Zullo

This paper gives an excellent review of the arm regeneration process and timing with photos and diagrams of the stages.


Abstract The ability to regenerate whole-body structures has been long studied in both vertebrate and invertebrate animal models. Due to this regeneration capability here we propose the use of the Cephalopod Octopus vulgaris as a model of regeneration. We investigated the involvement of acetylcholinesterase (AChE) in the octopus arm regeneration. AChE has been demonstrated to have non-cholinergic functions in various cell types and to be involved in the regulation of cell proliferation, differentiation and apoptosis. In order to follow cell replacement in the octopus arm, we first assessed the expression of specific markers involved in cellular proliferation (AgNOR and PCNA). We showed that the activity of the enzyme AChE is related to the proliferation stage of the arm regenerative process. In the very initial stages of regrowth when most of the proliferation activity was at the level of the ‘blastema’ the cholinesterase activity was very low. AChE activity climbed slowly during the subsequent phase of cellular multiplication and, by the onset of morphogenesis, the activity rose sharply and active myogenesis was observed. AChE activity decreased then till reaching basal level at the time when the process of histogenesis occurred and the reestablishment of all the structures became evident. Interestingly AgNOR and AChE assay showed a similar trend in particular during the stages when the morphogenesis was mostly dependent upon cell proliferation. We suggest that AChE protein may have an important influence in the process of regeneration and that it could be considered as a potential target to promote or regulate the regenerative process.

NOTE the reference to Robyn's paper:
Crook and Walters, 2011
  • R.J. Crook, E.T. Walters
  • Nociceptive behavior and physiology of molluscs: animal welfare implications
  • ILAR J., 52 (2011), pp. 185–195
 

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DWhatley

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DWhatley said:
Octopus arm regeneration: Role of acetylcholinesterase during morphological modification Sara Maria Fossati, Francesca Carella, Gionata De Vico, Fabio Benfenatia, Letizia Zullo

This paper gives an excellent review of the arm regeneration process and timing with photos and diagrams of the stages.


Abstract The ability to regenerate whole-body structures has been long studied in both vertebrate and invertebrate animal models. Due to this regeneration capability here we propose the use of the Cephalopod Octopus vulgaris as a model of regeneration. We investigated the involvement of acetylcholinesterase (AChE) in the octopus arm regeneration. AChE has been demonstrated to have non-cholinergic functions in various cell types and to be involved in the regulation of cell proliferation, differentiation and apoptosis. In order to follow cell replacement in the octopus arm, we first assessed the expression of specific markers involved in cellular proliferation (AgNOR and PCNA). We showed that the activity of the enzyme AChE is related to the proliferation stage of the arm regenerative process. In the very initial stages of regrowth when most of the proliferation activity was at the level of the ‘blastema’ the cholinesterase activity was very low. AChE activity climbed slowly during the subsequent phase of cellular multiplication and, by the onset of morphogenesis, the activity rose sharply and active myogenesis was observed. AChE activity decreased then till reaching basal level at the time when the process of histogenesis occurred and the reestablishment of all the structures became evident. Interestingly AgNOR and AChE assay showed a similar trend in particular during the stages when the morphogenesis was mostly dependent upon cell proliferation. We suggest that AChE protein may have an important influence in the process of regeneration and that it could be considered as a potential target to promote or regulate the regenerative process.

NOTE the reference to Robyn's paper:
Crook and Walters, 2011
  • R.J. Crook, E.T. Walters
  • Nociceptive behavior and physiology of molluscs: animal welfare implications
  • ILAR J., 52 (2011), pp. 185–195
Katherine Harmon's summary review of this article in her Octopus Chronicles blog entry, How Octopus Arms Regenerate With Ease
 

DWhatley

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Arm regeneration in two species of cuttlefish Sepia officinalis and Sepia pharaonis
Jedediah Tressler,Francis Maddox,Eli Goodwin,Zhuobin Zhang,Nathan J. Tublitz August 2013 - Subscription or pay by article required

Abstract

To provide quantitative information on arm regeneration in cuttlefish, the regenerating arms of two cuttlefish species, Sepia officinalis and Sepia pharaonis, were observed at regular intervals after surgical amputation. The third right arm of each individual was amputated to ~10–20 % starting length. Arm length, suction cup number, presence of chromatophores, and behavioral measures were collected every 2–3 days over a 39-day period and compared to the contralateral control arm. By day 39, the regenerating arm reached a mean 95.5 ± 0.3 % of the control for S. officinalis and 94.9 ± 1.3 % for S. pharaonis. The process of regeneration was divided into five separate stages based on macroscopic morphological events: Stage I (days 0–3 was marked by a frayed leading edge; Stage II (days 4–15) by a smooth hemispherical leading edge; Stage III (days 16–20) by the appearance of a growth bud; Stage IV (days 21–24) by the emergence of an elongated tip; and Stage V (days 25–39) by a tapering of the elongated tip matching the other intact arms. Behavioral deficiencies in swimming, body postures during social communication, and food manipulation were observed immediately after arm amputation and throughout Stages I and II, returning to normal by Stage III. New chromatophores and suction cups in the regenerating arm were observed as early as Stage II and by Stage IV suction cup number equaled that of control arms. New chromatophores were used in the generation of complex body patterns by Stage V. These results show that both species of cuttlefish are capable of fully regenerating lost arms, that the regeneration process is predictable and consistent within and across species, and provide the first quantified data on the rate of arm lengthening and suction cup addition during regeneration.
 

Tintenfisch

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Damien;n281833 said:
Is there any data about comparison between arms and tentacules regeneration for a decapod?
Actually this would be very interesting to look into, especially across species where tentacles are lost at early (or late) life stages vs retained throughout. For example, octopoteuthids (and some other families) lose the tentacles as paralarvae and never regenerate them, but must be able to regenerate arms (and arm tips since these can be jettisoned); onychoteuthids often lose the tentacles around maturity and don't regrow them, but will begin to regenerate them if lost earlier (this would be particularly interesting to look at--when does the regeneration cue switch off?), while some others retain tentacles all the way through the lifespan and so presumably will start regenerating them no matter when they're lost.

Hmmmmmmmmm.... :read:
 

SepiaInc

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For example, octopoteuthids (and some other families) lose the tentacles as paralarvae and never regenerate them, but must be able to regenerate arms
This tidbit is very intriguing considering other animals often see a hyper-regenerative ability at early stages and lose regeneration with aging, especially in muscle. I speak from a vertebrate perspective, but the classical amphibian models even lose their abilities after inducing metamorphosis.

Does anyone know if cephs have a quiescent stem population perhaps similar to pericytes or satellite cells? It'd be interesting to look further into which populations are contributing in that Fossati paper. Maybe they can dedifferentiate like Gymnotiform fishes.
 

DWhatley

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The surprising resilience of octopus tentacles [Video]

Self-Recognition Mechanism between Skin and Suckers Prevents Octopus Arms from Interfering with Each Other
Nir Nesher, Guy Levy, Frank W. Grasso, Binyamin Hochner 2014 (subscription)

Highlights
  • •Octopus suckers have a strong tendency to attach to any substrate they contact
  • •This raises the question of why octopus arms do not grab or interfere with each other
  • •Here it is shown that chemical signals from octopus skin inhibit the attachment reflex
  • •Thus, constraining the arms from interfering with each other simplifies motor control
Summary
Controlling movements of flexible arms is a challenging task for the octopus because of the virtually infinite number of degrees of freedom (DOFs) [ 1, 2 ]. Octopuses simplify this control by using stereotypical motion patterns that reduce the DOFs, in the control space, to a workable few [ 2 ]. These movements are triggered by the brain and are generated by motor programs embedded in the peripheral neuromuscular system of the arm [ 3–5 ]. The hundreds of suckers along each arm have a tendency to stick to almost any object they contact [ 6–9 ]. The existence of this reflex could pose significant problems with unplanned interactions between the arms if not appropriately managed. This problem is likely to be accentuated because it is accepted that octopuses are “not aware of their arms” [ 10–14 ]. Here we report of a self-recognition mechanism that has a novel role in motor control, restraining the arms from interfering with each other. We show that the suckers of amputated arms never attach to octopus skin because a chemical in the skin inhibits the attachment reflex of the suckers. The peripheral mechanism appears to be overridden by central control because, in contrast to amputated arms, behaving octopuses sometime grab amputated arms. Surprisingly, octopuses seem to identify their own amputated arms, as they treat arms of other octopuses like food more often than their own. This self-recognition mechanism is a novel peripheral component in the embodied organization of the adaptive interactions between the octopus’s brain, body, and environment [ 15, 16 ].
 

DWhatley

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Octobot uses webbed arms to swim faster
by Meghan Rosen September 17, 2014

CHICAGO —Webbed underarms can turn a sluggish robotic octopus into a speed demon.
A squishy membrane connecting the machine’s eight arms helps the bot scoot through water nearly twice as fast as octobots without webs, researchers reported at the IEEE/RSJ International Conference on Intelligent Robots and Systems on September 15.
Inspired by Octopus vulgaris, the well-known sea creature with arms connected by a fleshy, skirtlike mantle, computer scientist Dimitris Tsakiris and colleagues decided to give a makeover to the robotic octopus they had previously developed. The earlier, webless version could propel itself at up to 100 millimeters per second by slowly opening stiff plastic arms and then snapping them together.
But with arms and a web made of soft silicone, the shoe box–sized bot swam at up to 180 millimeters per second. The web helps the octobot generate more force, so it can push through water faster than using arms alone.
Skittish sea animals seem unfrightened by the lifelike bot, said Tsakiris, of the Foundation for Research and Technology- Hellas in Heraklion, Greece. When researchers took the faux octopus for a swim in the Mediterranean, tiny fish tagged along.
 

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