Gap Junctional Blockade Stochastically Induces Different Species-Specific Head Anatomies in Genetically Wild-Type Girardia dorotocephala Flatworms

Int J Mol Sci · 2015 · Mixed · Low evidence

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MixedLow evidencePaper 6822

Study snapshot

PublicationInt J Mol Sci · 2015

Study typeanimal

Reported directionMixed

Evidence ratingLow

Abstract

The shape of an animal body plan is constructed from protein components encoded by the genome. However, bioelectric networks composed of many cell types have their own intrinsic dynamics, and can drive distinct morphological outcomes during embryogenesis and regeneration. Planarian flatworms are a popular system for exploring body plan patterning due to their regenerative capacity, but despite considerable molecular information regarding stem cell differentiation and basic axial patterning, very little is known about how distinct head shapes are produced. Here, we show that after decapitation in G. dorotocephala, a transient perturbation of physiological connectivity among cells (using the gap junction blocker octanol) can result in regenerated heads with quite different shapes, stochastically matching other known species of planaria (S. mediterranea, D. japonica, and P. felina). We use morphometric analysis to quantify the ability of physiological network perturbations to induce different species-specific head shapes from the same genome. Moreover, we present a computational agent-based model of cell and physical dynamics during regeneration that quantitatively reproduces the observed shape changes. Morphological alterations induced in a genomically wild-type G. dorotocephala during regeneration include not only the shape of the head but also the morphology of the brain, the characteristic distribution of adult stem cells (neoblasts), and the bioelectric gradients of resting potential within the anterior tissues. Interestingly, the shape change is not permanent; after regeneration is complete, intact animals remodel back to G. dorotocephala-appropriate head shape within several weeks in a secondary phase of remodeling following initial complete regeneration. We present a conceptual model to guide future work to delineate the molecular mechanisms by which bioelectric networks stochastically select among a small set of discrete head morphologies. Taken together, these data and analyses shed light on important physiological modifiers of morphological information in dictating species-specific shape, and reveal them to be a novel instructive input into head patterning in regenerating planaria.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal

Effect directionmixed

PopulationGirardia dorotocephala planarian flatworms after decapitation/regeneration

Sample sizeNot supplied

Exposuretransient perturbation during regeneration using the gap junction blocker octanol

Evidence strengthLowConfidence: 95% · Peer reviewed: yes

Main findings

In decapitated G. dorotocephala, transient gap junction blockade with octanol during regeneration induced stochastic regenerated head shapes resembling other planarian species. Associated changes were also reported in brain morphology, neoblast distribution, and anterior resting-potential gradients, and the altered head shapes later remodeled back to the species-appropriate form over several weeks.

Outcomes measured

head shape morphology during regeneration
brain morphology
distribution of adult stem cells (neoblasts)
bioelectric gradients of resting potential within anterior tissues
secondary remodeling back to species-appropriate head shape

Limitations

Animal study
Sample size not stated in the abstract
Intervention was pharmacologic gap junction blockade rather than EMF exposure
Mechanistic details are presented as a conceptual/computational model rather than fully resolved in the abstract

View raw extracted JSON

{
  "study_type": "animal",
  "exposure": {
    "band": null,
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": "transient perturbation during regeneration using the gap junction blocker octanol"
  },
  "population": "Girardia dorotocephala planarian flatworms after decapitation/regeneration",
  "sample_size": null,
  "outcomes": [
    "head shape morphology during regeneration",
    "brain morphology",
    "distribution of adult stem cells (neoblasts)",
    "bioelectric gradients of resting potential within anterior tissues",
    "secondary remodeling back to species-appropriate head shape"
  ],
  "main_findings": "In decapitated G. dorotocephala, transient gap junction blockade with octanol during regeneration induced stochastic regenerated head shapes resembling other planarian species. Associated changes were also reported in brain morphology, neoblast distribution, and anterior resting-potential gradients, and the altered head shapes later remodeled back to the species-appropriate form over several weeks.",
  "effect_direction": "mixed",
  "limitations": [
    "Animal study",
    "Sample size not stated in the abstract",
    "Intervention was pharmacologic gap junction blockade rather than EMF exposure",
    "Mechanistic details are presented as a conceptual/computational model rather than fully resolved in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.95,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "planaria",
    "Girardia dorotocephala",
    "gap junction blockade",
    "octanol",
    "bioelectric networks",
    "regeneration",
    "head morphology",
    "brain morphology",
    "neoblasts",
    "resting potential"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.3390/ijms161126065
PubMed: 26610482

Read the original paper →

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