Chaetognatha

Harzsch, Steffen; Müller, Carsten H. G.; Perez, Yvan

doi:10.1007/978-3-7091-1862-7_10

Cited by 6 publications

(6 citation statements)

References 66 publications

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“…Many different roles have been proposed for the corona ciliata including excretory (chaetognaths lack nephridia), (chemo)sensory, or secretory (glandular) function (Shinn 1997;Müller et al 2014;Harzsch et al 2015). Our study demonstrates that sce-cryptochrome is expressed in distal and proximal cells of the corona ciliata suggesting that cells of this organ may be involved in circadian entrainment ( Fig.…”

Section: The Corona Ciliata An Organ With Light-sensitive Receptors?mentioning

confidence: 58%

“…aspects of gastrulation process) as well as protostomes (nervous system development). Hence their phylogenetic position has been contentious for a long time until phylogenetic analyses recently placed them within the Gnathifera (summarized by Harzsch et al 2015;Marlétaz et al 2019).…”

Section: Introductionmentioning

confidence: 99%

“…In the present study we investigated the presence of opsins and other light-sensitive proteins in developmental stages and adults of the epibenthic chaetognath Spadella cephaloptera. This species possesses inverted photoreceptors and is probably the best investigated chaetognath with respect to its nervous and sensory systems (summarized in Harzsch et al 2015). To this end, we 6 searched for homologs of opsins and other light-sensitive proteins and identified single-copy orthologs of xenopsin and peropsin as well as cryoptochrome.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of eyes, photoreceptors and opsins in developmental stages of the chaetognath Spadella cephaloptera

Wollesen¹,

Monje

Oel

et al. 2019

Preprint

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The phylogenetic position of chaetognaths has been debated for decades, however recently they have been grouped into the Gnathifera, sister taxon to the Lophotrochozoa. Chaetognaths possess photoreceptor cells that are anatomically unique and arranged remarkably different in the eyes of the various species. Studies investigating eye development and underlying gene regulatory networks are so far missing.In order to gain insights into the development and the molecular toolkit of chaetognath photoreceptors and eyes a new transcriptome of the epibenthic species Spadella cephaloptera was searched for opsins. Our screen revealed single-copies of xenopsin and peropsin and gene expression analyses demonstrated that only xenopsin is expressed in photoreceptor cells of the developing lateral eyes. Adults likewise exhibit two xenopsin+ photoreceptor cells in each of their lateral eyes. Beyond that, a single cryptochrome gene was uncovered and found coexpressed with xenopsin in some photoreceptor cells of the lateral developing eye. In addition, it is co-expressed with peropsin in the cerebral ganglia, a condition reminiscent of a non-visual photoreceptive zone in the apical nervous system of the annelid Platynereis dumerilii that performs circadian entrainment and melatonin release. Cryptochrome expression was also detected in cells of the corona ciliata, a circular organ in the posterior dorsal head region that has been attributed several functions arguing for an involvement of this organ in circadian entrainment. Our study demonstrates the importance to investigate representatives of the Gnathifera, a clade that has been neglected with respect to developmental studies and that might contribute to unravel the evolution of spiralian and bilaterian body plans.

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Section: The Corona Ciliata An Organ With Light-sensitive Receptors?mentioning

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization of eyes, photoreceptors and opsins in developmental stages of the chaetognath Spadella cephaloptera

Wollesen¹,

Monje

Oel

et al. 2019

Preprint

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“…As a major macroplanktonic component without respiratory or circulatory systems, chaetognaths exhibit traits reminiscent of deuterostomes (e.g., aspects of the gastrulation process) as well as of protostomes (e.g., nervous system development). Hence, their phylogenetic position had been contentious until phylogenetic analyses recently placed them within the Gnathifera (summarized by Harzsch & Wanninger, 2010 ; Harzsch et al, 2015 ; Marlétaz et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

“…In the present study, we investigated the presence of opsins and other light‐sensitive proteins in developmental stages and adults of the epibenthic chaetognath Spadella cephaloptera . This species possesses inverted photoreceptors and is probably the best investigated chaetognath with respect to its nervous and sensory systems (summarized in Harzsch et al, 2015 ; Müller et al, 2019 ). To this end, we searched for homologs of opsins and other light‐sensitive proteins and identified two copies of xenopsin and single‐copy orthologs of peropsin as well as cryoptochrome .…”

Section: Introductionmentioning

confidence: 99%

Characterization of eyes, photoreceptors, and opsins in developmental stages of the arrow wormSpadella cephaloptera(Chaetognatha)

et al. 2023

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The phylogenetic position of chaetognaths, or arrow worms, has been debated for decades, however recently they have been grouped into the Gnathifera, a sister clade to all other Spiralia. Chaetognath photoreceptor cells are anatomically unique by exhibiting a highly modified cilium and are arranged differently in the eyes of the various species. Studies investigating eye development and underlying gene regulatory networks are so far missing. To gain insights into the development and the molecular toolkit of chaetognath photoreceptors and eyes a new transcriptome of the epibenthic species Spadella cephaloptera was searched for opsins. Our screen revealed two copies of xenopsin and a single copy of peropsin. Gene expression analyses demonstrated that only xenopsin1 is expressed in photoreceptor cells of the developing lateral eyes. Adults likewise exhibit two xenopsin1 + photoreceptor cells in each of their lateral eyes. Beyond that, a single cryptochrome gene was uncovered and found to be expressed in photoreceptor cells of the lateral developing eye. In addition, cryptochrome is also expressed in the cerebral ganglia in a region in which also peropsin expression was observed. This condition is reminiscent of a nonvisual photoreceptive zone in the apical nervous system of the annelid Platynereis dumerilii that performs circadian entrainment and melatonin release.Cryptochrome is also expressed in cells of the corona ciliata, an organ in the posterior dorsal head region, indicating a role in circadian entrainment. Our study highlights the importance of the Gnathifera for unraveling the evolution of photoreceptors and eyes in Spiralia and Bilateria.

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Zoo- and Ichthyoplankton Communities of Pelagic Ecosystems in the Western Tropical Atlantic

Schwamborn

Neumann‐Leitão²,

Lira³

et al. 2023

The Latin American Studies Book Series

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Chaetognatha

Cited by 6 publications

References 66 publications

Characterization of eyes, photoreceptors and opsins in developmental stages of the chaetognath Spadella cephaloptera

Characterization of eyes, photoreceptors and opsins in developmental stages of the chaetognath Spadella cephaloptera

Characterization of eyes, photoreceptors, and opsins in developmental stages of the arrow wormSpadella cephaloptera(Chaetognatha)

Zoo- and Ichthyoplankton Communities of Pelagic Ecosystems in the Western Tropical Atlantic

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