Ultrastructural demonstration of iodine binding and peroxidase activity in the endostyle of Oikopleura dioica (appendicularia)

Fredriksson, G.; Öfverholm, Torsten; Ericson, Lars

doi:10.1016/0016-6480(85)90348-x

Cited by 23 publications

(13 citation statements)

References 17 publications

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“…During the first half of the twentieth century, several authors described the histology and morphology of the larvacean endostyle (Salensky, 1904;Ihle, 1907;Martini, 1909;Lohmann, 1933;Berrill, 1950). Decades later, high-resolution light and electron micrographs and cytochemistry revealed the cytological structure and distribution of histochemical activities in the larvacean endostyle (Olsson, 1963(Olsson, , 1965Fredriksson et al, 1985). To complement past observations on fixed specimens, we investigated live animals by differential interference contrast (DIC) microscopy.…”

Section: Oikopleura Dioicamentioning

confidence: 99%

“…1B,C). The two central rows of the corridor cells correspond to the iodine-binding zones (Fredriksson et al, 1985). The corridor contains numerous giant cilia (GC) that help direct and wind the food-trapping secretions of the endostyle into a strand that enters the pharynx lumen (Fig.…”

Section: Oikopleura Dioicamentioning

confidence: 99%

“…1B-D). Previous cytochemical studies suggest that the iodination of proteins secreted by the glandular cells is probably catalyzed by extracellular peroxidases when the secreted substance passes the corridor cells toward the pharynx (Fredriksson et al, 1985). Overall, our observations in live animals complement past comparative studies between larvaceans and other chordates, and are consistent with the idea that the endostyle of Oikopleura shares a ground plan with all other known endostyles in chordates with respect to the organization of various types of cells involved in food-trapping and iodinating functions, and the fact that urochordates, cephalochordates, and vertebrates share the genetic machinery that patterns different functional zones in the dorsoventral axis (Hiruta et al, 2005).…”

Section: Oikopleura Dioicamentioning

confidence: 99%

“…(2) In the central portion of the endostyle, the dorsal, Pax2/5/8a-expressing region (red in Fig. 4B) includes the rows of corridor cells that show peroxidase activity and bind iodine in Oikopleura (Fredriksson et al, 1985). Ventrally, the central portion expresses Pax2/5/8b (purple in Fig.…”

Section: Three-dimensional Reconstruction Of Ap Axial Patterning In Tmentioning

confidence: 99%

“…This homology, originally based on the reorganization of the larval endostyle into the adult thyroid in lampreys (Muller, 1873), is supported by iodine binding, peroxidase activity, thyroglobulin, and calcitonin-like cells both in endostyles and in thyroids (Gorbman and Creaser, 1943;Barrington, 1957;Thorpe et al, 1972;Thorndyke, 1978;Thorndyke and Probert, 1979;Kobayashi et al, 1983;Fredriksson et al, 1985Fredriksson et al, , 1988.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of the thyroid: Anterior–posterior regionalization of theOikopleuraendostyle revealed byOtx,Pax2/5/8, andHox1expression

Cañestro

Bassham

Postlethwait

2008

Developmental Dynamics

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The thyroid in vertebrates and its homolog, the endostyle in nonvertebrate chordates, share a molecular code for dorsoventral patterning. Little is yet known, however, about mechanisms that pattern the endostyle's anterior-posterior (AP) axis. To extend our understanding of thyroid development and evolution, we studied Oikopleura dioica, a larvacean urochordate that retains a chordate body plan as adults. Transcription factor expression domains revealed AP regionalization of the endostyle, with expression of Otx rostrally, Hox1 caudally, and two Pax2/5/8 paralogs centrally. Comparative analysis suggested that the endostyle of stem chordates expressed orthologs of these genes and that ancestral subfunctions partitioned differentially among lineages. Because the ordered expression of Otx, Pax2/5/8, and Hox1 displays patterning in both the endodermally derived endostyle and the ectodermally derived central nervous system, we propose that this gene set belonged to the developmental genetic toolkit of stem bilaterians and repeatedly provided AP positional information in various developmental situations.

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Section: Oikopleura Dioicamentioning

confidence: 99%

Section: Oikopleura Dioicamentioning

confidence: 99%

Section: Oikopleura Dioicamentioning

confidence: 99%

Section: Three-dimensional Reconstruction Of Ap Axial Patterning In Tmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evolution of the thyroid: Anterior–posterior regionalization of theOikopleuraendostyle revealed byOtx,Pax2/5/8, andHox1expression

Cañestro

Bassham

Postlethwait

2008

Developmental Dynamics

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The basal chordate amphioxus as a simple model for elucidating developmental mechanisms in vertebrates

Koop

Holland

2008

Birth Defects Research Pt C

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This review examines the basal chordate, amphioxus, as a simple model for providing insights into the development and evolution of the vertebrates, with which it shares many features, including a pharynx perforated with gill slits, a dorsal nerve cord, segmented muscles, and a notochord. Conversely, amphioxus is simpler than vertebrates in lacking neural crest and paired cephalic sensory organs. Amphioxus embryos are less derived than those of vertebrates, because it lacks large quantities of yolk and/or extra-embryonic tissues. Embryogenesis involves only a simple folding of tissue layers. In addition, the amphioxus genome lacks the large-scale gene duplications of vertebrates. However, in spite of the comparative simplicity of amphioxus, its developmental mechanisms are proving to be highly conserved with those of vertebrates. Thus, studies of amphioxus development can shed light on similar, but more complex, development of vertebrates. Such studies are especially interesting for their insights into the genetic basis of craniofacial birth defects in humans.

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Thyroid‐like hormone signaling in invertebrates and its potential role in initial screening of thyroid hormone system disrupting chemicals

Morthorst

Holbech

Crozé

et al. 2022

Integr Envir Assess & Manag

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This review examines the presence and evolution of thyroid-like systems in selected aquatic invertebrates to determine the potential use of these organisms in screens for vertebrate thyroid hormone axis disrupting chemicals (THADCs). Such a screen might support the phasing out of some vertebrate testing. Although arthropods including crustaceans do not contain a functional thyroid signaling system, elements of such a system exist in the aquatic phyla mollusks, echinoderms, tunicates, and cephalochordates. These phyla can synthesize thyroid hormone, which has been demonstrated in some groups to induce the nuclear thyroid hormone receptor (THR). Thyroid hormone may act in these phyla through interaction with a membrane integrin receptor. Thyroid hormone regulates inter alia metamorphosis but, unlike in vertebrates, this does not occur via receptor activation by the ligands triiodothyronine (T3) and thyroxine (T4). Instead, the unliganded nuclear receptor itself controls metamorphosis in mollusks, echinoderms, and tunicates, whereas the T3 derivative tri-iodothyroacetic acid (TRIAC) acts as a THR ligand in cephalochordates. In view of this, it may be possible to develop an invertebrate-based screen that is sensitive to vertebrate THADCs that interfere with thyroid hormone synthesis or metabolism along with interaction with membrane receptors. The review makes some recommendations for the need to develop an appropriate test method.

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Ultrastructural demonstration of iodine binding and peroxidase activity in the endostyle of Oikopleura dioica (appendicularia)

Cited by 23 publications

References 17 publications

Evolution of the thyroid: Anterior–posterior regionalization of theOikopleuraendostyle revealed byOtx,Pax2/5/8, andHox1expression

Evolution of the thyroid: Anterior–posterior regionalization of theOikopleuraendostyle revealed byOtx,Pax2/5/8, andHox1expression

The basal chordate amphioxus as a simple model for elucidating developmental mechanisms in vertebrates

Thyroid‐like hormone signaling in invertebrates and its potential role in initial screening of thyroid hormone system disrupting chemicals

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