The neuroanatomy of the Hawaiian bobtail squid juvenile bacterial light organ
Abstract
Background: Recent studies have shown that symbiotic bacteria can have drastic effects on host neurobiology, but few simple, accessible models currently exist in which to study these interactions. Hawaiian bobtail squid ( Euprymna scolopes ) participate in a binary symbiosis with the bacterium Vibrio fischeri , a population of which resides in a specialized hindgut-derived organ called the light organ. Upon colonization by V. fischeri , the light organ undergoes transcriptional changes that suggest neurons are among the cell types impacted by the initiation of symbiosis, but the nascent light organ’s innervation has remained uncharacterized.
Results: The light organ-associated nervous system (LONS) in hatchling E. scolopes is a remarkably complex segment of the peripheral nervous system. The LONS is largely plexiform and originates from two primary nerves connected by a local commissure. The abundance of synapsin-like immunoreactivity indicates that the lobe plexus is highly interconnected. We also highlight a small number of serotonin-like immunoreactive neurites innervating the anterior appendages that are poised to be directly impacted by symbiont-driven post-embryonic development. Finally, we present evidence that a limited but morphologically diverse population of neurons reside within the light organ and are often located near internal symbiont-interacting structures.
Conclusions: Our results show that the LONS is structurally and molecularly complex and exhibits traits characteristic of an immature nervous system, suggesting that it may undergo substantial post-embryonic refinement. This initial characterization of the LONS provides a foundation from which to investigate how beneficial bacterial symbionts affect host peripheral neurobiology in a tractable model system.
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BibTeX
@article{walker2026neuroanatomy,
title = {{The neuroanatomy of the Hawaiian bobtail squid juvenile bacterial light organ}},
author = {Alice Breaux Walker and Elizabeth Victoria Xiu Widun and Elizabeth Anne Chapman Heath-Heckman},
journal = {BMC Biology},
year = {2026},
month = sep,
doi = {10.1186/s12915-026-02735-z},
url = {https://link.springer.com/10.1186/s12915-026-02735-z},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The neuroanatomy of the Hawaiian bobtail squid juvenile bacterial light organ
AU - Alice Breaux Walker
AU - Elizabeth Victoria Xiu Widun
AU - Elizabeth Anne Chapman Heath-Heckman
PY - 2026
DA - 2026/09/30
JO - BMC Biology
DO - 10.1186/s12915-026-02735-z
UR - https://link.springer.com/10.1186/s12915-026-02735-z
AB - Background: Recent studies have shown that symbiotic bacteria can have drastic effects on host neurobiology, but few simple, accessible models currently exist in which to study these interactions. Hawaiian bobtail squid ( Euprymna scolopes ) participate in a binary symbiosis with the bacterium Vibrio fischeri , a population of which resides in a specialized hindgut-derived organ called the light organ. Upon colonization by V. fischeri , the light organ undergoes transcriptional changes that suggest neurons are among the cell types impacted by the initiation of symbiosis, but the nascent light organ’s innervation has remained uncharacterized. Results: The light organ-associated nervous system (LONS) in hatchling E. scolopes is a remarkably complex segment of the peripheral nervous system. The LONS is largely plexiform and originates from two primary nerves connected by a local commissure. The abundance of synapsin-like immunoreactivity indicates that the lobe plexus is highly interconnected. We also highlight a small number of serotonin-like immunoreactive neurites innervating the anterior appendages that are poised to be directly impacted by symbiont-driven post-embryonic development. Finally, we present evidence that a limited but morphologically diverse population of neurons reside within the light organ and are often located near internal symbiont-interacting structures. Conclusions: Our results show that the LONS is structurally and molecularly complex and exhibits traits characteristic of an immature nervous system, suggesting that it may undergo substantial post-embryonic refinement. This initial characterization of the LONS provides a foundation from which to investigate how beneficial bacterial symbionts affect host peripheral neurobiology in a tractable model system.
SN - 1741-7007
ER -