@article{crossref1856amphioxus,
    title = "Amphioxus Lanceolatus",
    year = "1856",
    journal = "Annals and Magazine of Natural History",
    url = "https://doi.org/10.1080/00222935608697647",
    doi = "10.1080/00222935608697647",
    number = "106",
    pages = "350-350",
    volume = "18"
}

@misc{hatschek1893the9,
    author = "Hatschek, B",
    title = "The amphioxus and its development",
    year = "1893",
    howpublished = "London, Sonnenschein; Translated and edited by J. Tuckey",
    note = "talkorigins\_source = {true}; raw\_reference = {Hatschek, B., 1893, The amphioxus and its development: London, Sonnenschein; Translated and edited by J. Tuckey.}"
}

@article{goodrich1902on8,
    author = "Goodrich, E. S",
    title = "On the structure of the execretory organs of Amphioxus, Part 1",
    year = "1902",
    journal = "Quarterly Journal of Microscopical Science, v. 45, p. 493-501",
    note = "talkorigins\_source = {true}; raw\_reference = {Goodrich, E. S., 1902, On the structure of the execretory organs of Amphioxus, Part 1: Quarterly Journal of Microscopical Science, v. 45, p. 493-501.}"
}

@article{dogiel1903das,
    author = "Dogiel, A. S.",
    title = "Das Periphere Nervensystem des Amphioxus (Branchiostoma Lanceolatum)",
    year = "1903",
    journal = "Beiträge und Referate zur Anatomie und Entwickelungsgeschichte",
    url = "https://doi.org/10.1007/bf02110551",
    doi = "10.1007/bf02110551",
    number = "1",
    openalex = "W2005412999",
    pages = "145-213",
    volume = "21"
}

@article{orton1913the11,
    author = "Orton, J. H",
    title = "The ciliary mechanisms on the gill and the mode of feeding in Amphioxus, Ascidians and Solenomyo togato",
    year = "1913",
    journal = "Journal of the Marine Biological Association of the United Kingdom, v. 10, p. 19-49",
    note = "talkorigins\_source = {true}; raw\_reference = {Orton, J. H., 1913, The ciliary mechanisms on the gill and the mode of feeding in Amphioxus, Ascidians and Solenomyo togato: Journal of the Marine Biological Association of the United Kingdom, v. 10, p. 19-49.}"
}

@article{boeke1935the2,
    author = "Boeke, J",
    title = "The autonomic (enteric) nrevous system of Amphioxus lanceolatus",
    year = "1935",
    journal = "Quarterly Journal of Microscopical Science, v. 77, p. 623- 658",
    note = "talkorigins\_source = {true}; raw\_reference = {Boeke, J., 1935, The autonomic (enteric) nrevous system of Amphioxus lanceolatus: Quarterly Journal of Microscopical Science, v. 77, p. 623- 658.}"
}

@article{barrington1938the1,
    author = "Barrington, E. J. W",
    title = "The digestive system of Amphioxus ( Branchiostoma) lanceolatus",
    year = "1938",
    journal = "Philosophical Transactions of the Royal Society, London B, v. 228, p. 269-311",
    note = "talkorigins\_source = {true}; raw\_reference = {Barrington, E. J. W., 1938, The digestive system of Amphioxus ( Branchiostoma) lanceolatus: Philosophical Transactions of the Royal Society, London B, v. 228, p. 269-311.}"
}

@article{doi101242jcss3898359,
    author = "Whiting, H. P.",
    title = "Nervous Structure of the Spinal Cord of the Young Larval Brook-Lamprey",
    year = "1948",
    journal = "Journal of Cell Science",
    abstract = "ABSTRACT It is intended to describe here the spinal cord of recently hatched ammocoetes of Lampetra planeri (Bloch). Particular attention will be given to those neurons which may be involved in the somatic sensori-motor arc. It is hoped to base upon this description a subsequent account of the embryo and young ammocoete, which will deal with the successive stages of nervous structure and their relation to the successive patterns of behaviour.",
    url = "https://doi.org/10.1242/jcs.s3-89.8.359",
    doi = "10.1242/jcs.s3-89.8.359",
    openalex = "W2185052337"
}

@article{bone1958the3,
    author = "Bone, Q",
    title = "The central nervous system in larval acraniates",
    year = "1958",
    journal = "Quarterly Journal of Microscopical Science, v. 100, p. 509-527",
    note = "talkorigins\_source = {true}; raw\_reference = {Bone, Q., 1958, The central nervous system in larval acraniates: Quarterly Journal of Microscopical Science, v. 100, p. 509-527.}"
}

@article{bone1959the,
    author = "Bone, Quentin",
    title = "The Central Nervous System in Larval Acraniates",
    year = "1959",
    journal = "Journal of Cell Science",
    abstract = "This paper describes a part of the organization of the spinal cord of the larva of the Acrania, dealing chiefly with those tracts and cell groups that are probably concerned. with the control of the swimming pattern. These observations serve as a basis for the comparison of the organization of the cord of the larva with that of the adult, and with that known for the larvae of the Agnatha and higher vertebrates. Other observations are concerned with the arrangement of the peripheral nervous system, which differs in some respects from that of the adult. The first section deals with the arrangement of the fibre tracts in the cord, and of the cell-bodies which give rise to these fibres. The form and connexions of the giant cells are then described; it is shown that these cells are equivalent to the Rohon-Beard sensory cells of vertebrate embryos. They send peripheral processes out through dorsal root nerves, but they differ from the vertebrate sensory neurones in their greatly enlarged dendrite field and the longitudinal axon in the cord. Thirdly, the innervation of the gill musculature is described. A ventro-lateral asymmetrical nerve is found, formed by the junction of fibres from the right anterior dorsal root nerves. Lastly, the arrangement of the whole system is discussed in relation to the systems found in the larval stages of other primitive chordates.",
    url = "https://doi.org/10.1242/jcs.s3-100.52.509",
    doi = "10.1242/jcs.s3-100.52.509",
    number = "52",
    openalex = "W2219906851",
    pages = "509-527",
    volume = "S3-100",
    references = "doi101002cne900240205, doi101021ed033p3572, doi1023071535762"
}

@article{bone1960the4,
    author = "Bone, Q",
    title = "The central nervous system in amphioxus",
    year = "1960",
    journal = "Journal of Comparative Neurology, v. 115, p. 27-64",
    note = "talkorigins\_source = {true}; raw\_reference = {Bone, Q., 1960, The central nervous system in amphioxus: Journal of Comparative Neurology, v. 115, p. 27-64.}"
}

@article{doi101002cne901150105,
    author = "Bone, Q.",
    title = "The central nervous system in amphioxus",
    year = "1960",
    journal = "The Journal of Comparative Neurology",
    url = "https://doi.org/10.1002/cne.901150105",
    doi = "10.1002/cne.901150105",
    openalex = "W2030707749",
    references = "bone1959the, dogiel1903das, doi101007bf02933895, doi101007bf02979946, doi101007bf02980498, doi1010970000505319361100000044, doi1010970000505319371100000043, doi101098rspl18890015, doi101111j146363951948tb00032x, doi101242jcss3898359, doi1023071535762, doi105962bhltitle159385, openalexw2298663468"
}

@article{bone1961the,
    author = "Bone, Quentin",
    title = "The organization of the atrial nervous system of amphioxus (Branchiostoma lanceolatum (Pallas))",
    year = "1961",
    journal = "Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences",
    abstract = "The Acrania possess an histologically complex peripheral nervous system, the atrial nervous system, lying just under the epithelium lining the atrium and covering the various organs within it. The system contains both sensory and motor components, and is especially rich in peripheral sensory cell bodies. It is in connexion with the central nervous system by way of the dorsal root nerves. Most of the motor axons entering the system pass to the cross-striated pterygial muscle flooring the atrium, others pass to the cross-striated trapezius muscles, and there is also a large ciliarymotor component, which controls the action of the lateral ciliary tracts of the gill bars. Unipolar sensory neurons are abundant upon the surface of the pterygial muscle, and are also found upon the parietal walls of the atrium. Multipolar sensory neurons are abundant upon the foregut and its diverticulum. The hindgut (outside the atrium) is more sparsely innervated, but occasional multipolar sensory neurons occur there. The multipolar neurons of the foregut and diverticulum appear to be in connexion one with another asynaptically, but their axons pass to the central nervous system. Similar sensory neurons of several types are found in the richly innervated atrio-coelomic funnels. The function of the atrial nervous system is not yet entirely understood, but it is probable that it is mainly concerned with the regulation of the feeding process, and with spawning. It is concluded that the system is not evidently homologous with the ‘sympathetic’ systems of the craniates, and that it is unwise at present to attempt to homologize the visceral nervous systems of the two groups.",
    url = "https://doi.org/10.1098/rstb.1961.0002",
    doi = "10.1098/rstb.1961.0002",
    number = "704",
    openalex = "W2013764007",
    pages = "241-269",
    volume = "243",
    references = "doi101002ar1090650110, doi101002cne901150105, doi101002jmor1050540103, doi101017s002531540001170x, doi1010381791345a0, doi101111j146363951956tb00047x, doi101111j1469185x1952tb01361x, doi101113expphysiol1958sp001305, doi105962bhltitle140340, doi105962bhltitle82144, holmes1953the"
}

@misc{bone1961the5,
    author = "Bone, Q",
    title = "The organisation of the atrial nervous system of Amphioxus",
    year = "1961",
    note = "talkorigins\_source = {true}; raw\_reference = {Bone, Q., 1961, The organisation of the atrial nervous system of Amphioxus}"
}

@misc{flood1968structure7,
    author = "Flood, P. R",
    title = "Structure of the segmental trunk muscle in amphioxus",
    year = "1968",
    howpublished = {with notes on the course and "endings" of the so-called ventral root fibres: Zeitschrift fr Zellforschung und Mikro-skopische Anatomie, v. 84, p. 389- 416},
    note = {talkorigins\_source = {true}; raw\_reference = {Flood, P. R., 1968, Structure of the segmental trunk muscle in amphioxus: with notes on the course and "endings" of the so-called ventral root fibres: Zeitschrift fr Zellforschung und Mikro-skopische Anatomie, v. 84, p. 389- 416.}}
}

@article{jefferies1973the10,
    author = "Jefferies, R. P. S",
    title = "The Ordovician fossil Lagynocystis pyramidalis (Barrande) and the ancestry of amphioxus",
    year = "1973",
    journal = "Philosophical Transactions of the Royal Society, London B, v. 265, p. 409-469",
    note = "talkorigins\_source = {true}; raw\_reference = {Jefferies, R. P. S., 1973, The Ordovician fossil Lagynocystis pyramidalis (Barrande) and the ancestry of amphioxus: Philosophical Transactions of the Royal Society, London B, v. 265, p. 409-469.}"
}

@article{webb1973the13,
    author = "Webb, J. E",
    title = "The role of the notochord in forward and reverse swimming and burrowing in the amphioxus Branchiostoma lanceolatum",
    year = "1973",
    journal = "Journal of Zoology, London, v. 170, p. 325-338",
    note = "talkorigins\_source = {true}; raw\_reference = {Webb, J. E., 1973, The role of the notochord in forward and reverse swimming and burrowing in the amphioxus Branchiostoma lanceolatum: Journal of Zoology, London, v. 170, p. 325-338.}"
}

@inproceedings{welsch1975the15,
    author = "Welsch, U",
    title = "The fine structure of the pharynx, cryptopodocytes and digestive system of amphioxus (Branchiostoma lanceolatum)",
    year = "1975",
    booktitle = "Symposium of the Zoological Society, London, v. 36, p. 17-41",
    note = "talkorigins\_source = {true}; raw\_reference = {Welsch, U., 1975, The fine structure of the pharynx, cryptopodocytes and digestive system of amphioxus (Branchiostoma lanceolatum): Symposium of the Zoological Society, London, v. 36, p. 17-41.}"
}

@article{webb1976a14,
    author = "Webb, J. E",
    title = "A Review of Swimming in Amphioxus, in Spencer Davies, P., ed., Perspectives in Experimental Biology, 1 of Zoology, Proceedings of the Fiftieth Anniversary Meeting of the Society of Experimental Biology",
    year = "1976",
    journal = "Oxford, Pergamon, v. 1, p. 447-454",
    note = "talkorigins\_source = {true}; raw\_reference = {Webb, J. E., 1976, A Review of Swimming in Amphioxus, in Spencer Davies, P., ed., Perspectives in Experimental Biology, 1 of Zoology, Proceedings of the Fiftieth Anniversary Meeting of the Society of Experimental Biology: Oxford, Pergamon, v. 1, p. 447-454.}"
}

@misc{rhr1979the12,
    author = "Rhr, H",
    title = "The circulatory system of Amphioxus (Branchiostona lanceolatum). A light microscope investigation based on intravascular injection technique",
    year = "1979",
    howpublished = "Acta Zoologica, Stockholm, v. 60, p. 1-18",
    note = "talkorigins\_source = {true}; raw\_reference = {Rhr, H., 1979, The circulatory system of Amphioxus (Branchiostona lanceolatum). A light microscope investigation based on intravascular injection technique: Acta Zoologica, Stockholm, v. 60, p. 1-18.}"
}

@article{doi101111j146363951982tb00757x,
    author = "Baatrup, Erik",
    title = "On the Structure of the Corpuscles of de Quatrefages (Branchiostoma lanceolatum (P))",
    year = "1982",
    journal = "Acta Zoologica",
    abstract = "Corpuscles of de Quatrefages in the rostral connective tissue of amphioxus have been serially sectioned and examined in the electron microscope. It is shown that each corpuscle is composed of one or a few main cells separated and enveloped by sheath cells. From the main cell two cilia protrude into a lumen formed by a bulge in the sheath. The ciliation of the main cell and its axonic continuation into one of the associated nerves suggests that this cell is a primary sensory neurone and the corpuscles of de Quatrefages probably mechanoreceptors.",
    url = "https://doi.org/10.1111/j.1463-6395.1982.tb00757.x",
    doi = "10.1111/j.1463-6395.1982.tb00757.x",
    openalex = "W2007096492",
    references = "dogiel1903das"
}

@article{doi101098rstb19860056,
    author = "White, JG and Southgate, Eileen and Thomson, J. Nichol and Brenner, Sydney",
    title = "The structure of the nervous system of the nematode Caenorhabditis elegans",
    year = "1986",
    journal = "Philosophical transactions of the Royal Society of London. Series B, Biological sciences",
    abstract = "The structure and connectivity of the nervous system of the nematode Caenorhabditis elegans has been deduced from reconstructions of electron micrographs of serial sections. The hermaphrodite nervous system has a total complement of 302 neurons, which are arranged in an essentially invariant structure. Neurons with similar morphologies and connectivities have been grouped together into classes; there are 118 such classes. Neurons have simple morphologies with few, if any, branches. Processes from neurons run in defined positions within bundles of parallel processes, synaptic connections being made en passant. Process bundles are arranged longitudinally and circumferentially and are often adjacent to ridges of hypodermis. Neurons are generally highly locally connected, making synaptic connections with many of their neighbours. Muscle cells have arms that run out to process bundles containing motoneuron axons. Here they receive their synaptic input in defined regions along the surface of the bundles, where motoneuron axons reside. Most of the morphologically identifiable synaptic connections in a typical animal are described. These consist of about 5000 chemical synapses, 2000 neuromuscular junctions and 600 gap junctions.",
    url = "https://doi.org/10.1098/rstb.1986.0056",
    doi = "10.1098/rstb.1986.0056",
    openalex = "W2160938187",
    references = "doi101083jcb171208"
}

@article{doi1023071541854,
    author = "Burke, Robert D. and Brand, D.G. and Bisgrove, Brent W.",
    title = "STRUCTURE OF THE NERVOUS SYSTEM OF THE AURICULARIA LARVA OF PARASTICOPUS CALIFORNICUS",
    year = "1986",
    journal = "Biological Bulletin",
    abstract = "The structure and organization of the larval nervous system of the holothurian, Parasticopus californicus, is described using glyoxylic acid-induced fluorescence, indirect immunofluorescence with antibodies against serotonin, and transmission and scanning electron microscopy. Tracts of catecholaminergic axons are located at the base of the ciliary bands and catecholaminergic nerve cell bodies are dispersed along the length of the ciliary bands. Clusters of catecholaminergic cells form a ganglion on the lower lip of the larva and a ganglion of serotonergic cells is located at the anterior tip of the larva. Serotonergic cells are scattered throughout the apical portion of the larva in the epidermis. Axon tracts identified only with TEM are located in the esophagus associated with the circumesophageal muscles. The neuroanatomy of the auricularia shares several features with larval forms of the other classes of echinoderms.",
    url = "https://doi.org/10.2307/1541854",
    doi = "10.2307/1541854",
    openalex = "W2513798547"
}

@article{crossref1990begonia,
    title = "BEGONIA AMPHIOXUS",
    year = "1990",
    journal = "Curtis's Botanical Magazine",
    url = "https://doi.org/10.1111/j.1467-8748.1990.tb00598.x",
    doi = "10.1111/j.1467-8748.1990.tb00598.x",
    number = "2",
    pages = "77-81",
    volume = "7"
}

@article{doi101002jmor1052070106,
    author = "Hirakow, Reiji and Kajita, N.",
    title = "Electron microscopic study of the development of amphioxus, Branchiostoma belcheri tsingtauense: The gastrula",
    year = "1991",
    journal = "Journal of Morphology",
    abstract = "The gastrulae of amphioxus were investigated by means of scanning and transmission electron microscopy (SEM and TEM) during 7 arbitrary stages that were seen about 4 to 10 hr after fertilization. Throughout gastrulation, SEM revealed subtle differences in cells of the blastoporal lip. In fractured specimens at early and middle stages, two opposing zones different in shape, size, and connection of the component cells were found: one which consists of columnar smaller cells in close contact in animal region and the other which is composed of round or polygonal larger cells in looser association in vegetal region. The polar body was found unexpectedly on the concave vegetal surface of the early gastrula in about 25\% of cases. This might be the result of migration of the polar body. A short cilium that later elongated was recognized on each cell at mid-gastrula stage. The cilia on the dorsal surface (the neural ectoderm) of the final-stage gastrula became shorter than those on the epidermal ectoderm. TEM of thin sections demonstrated that the cytoplasmic components of gastrula cells are essentially the same as those of cleavage cells. But, the homogeneous nucleus seen during cleavage changed into a heterogeneous structure in which a nucleolus and dense particles were seen. Until the late stage, regional characteristics of the gastrulae indicating definitively the anterior-posterior and dorso-ventral polarity were not detected in the present SEM and TEM study.",
    url = "https://doi.org/10.1002/jmor.1052070106",
    doi = "10.1002/jmor.1052070106",
    openalex = "W2140415852",
    references = "doi105962bhltitle140340, macbride1898the"
}

@article{doi101098rstb19940059,
    author = "Lacalli, Thurston C. and Holland, Nicholas D. and West, J. E.",
    title = "Landmarks in the anterior central nervous system of amphioxus larvae",
    year = "1994",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "Abstract The anterior end of the dorsal nerve cord of amphioxus is described at the 3-4 gill slit stage based on serial transmission electron microscopy and three-dimensional reconstruction, with special attention to structures that are potential landmarks for comparing amphioxus with other chordates. The larval nerve cord is divisible, at approximately the level of the first somite, into a short anterior region, the cerebral vesicle (c.v.), and an extended posterior region that is thought to include homologues of the vertebrate hindbrain and spinal cord. The c.v., in turn, has an anterior part with a tubular neural canal and a posterior part with a keyhole-shaped neural canal similar to that found in the rest of the cord. The junction between these two parts of the c.v. is marked by a cluster of infundibular cells. The anterior c.v., whose cells have cilia that point anteriorly, includes (i) a structure we call the frontal eye, consisting of a pigment spot and transverse rows of putative receptor and nerve cells, and (ii) several small ventral commissures bridging the major nerve tracts that run ventrolaterally along either side of the nerve cord. The posterior c.v., in contrast, contains cells whose cilia point posteriorly, and includes (i) the beginnings of the floorplate, which continues posteriorly through the rest of the nerve cord, (ii) the dorsal lamellar body, made up of cells with cilia that expand into flattened lamellae, and (iii) a large ventral commissure that incorporates fibres arising from cells of the lamellar body. Where probable homologues of c.v. structures can be identified in vertebrate brain, they are found in the diencephalon, which suggests the c.v. and the vertebrate diencephalon are, to a degree, homologous.",
    url = "https://doi.org/10.1098/rstb.1994.0059",
    doi = "10.1098/rstb.1994.0059",
    openalex = "W2034206853",
    references = "bone1959the, doi101002cne901150105, doi101007bf00348527, doi101007bf02028391, doi101016s0022532062800070, doi101111j1440169x198600569x, doi101111j146363951987tb00892x, doi101111j1469185x1989tb00471x, doi101152jn19814651018, doi101242dev1081121, doi101242dev1163653, doi101242jcss310052509, doi101523jneurosci1202004671992, doi101523jneurosci1301002851993, doi1023071541578, doi1023071541854, ruiz1991the"
}

@article{doi101242dev12292911,
    author = "Holland, Nicholas D. and Panganiban, Grace and Henyey, Erika L. and Holland, Linda Z.",
    title = "Sequence and developmental expression of AmphiDll, an amphioxus Distalless gene transcribed in the ectoderm, epidermis and nervous system: insights into evolution of craniate forebrain and neural crest",
    year = "1996",
    journal = "Development",
    abstract = "The dynamic expression patterns of the single amphioxus Distal-less homolog (AmphiDll) during development are consistent with successive roles of this gene in global regionalization of the ectoderm, establishment of the dorsoventral axis, specification of migratory epidermal cells early in neurulation and the specification of forebrain. Such a multiplicity of Distal-less functions probably represents an ancestral chordate condition and, during craniate evolution, when this gene diversified into a family of six or so members, the original functions evidently tended to be parcelled out among the descendant genes. In the amphioxus gastrula, AmphiDll is expressed throughout the animal hemisphere (presumptive ectoderm), but is soon downregulated dorsally (in the presumptive neural plate). During early neurulation, AmphiDll-expressing epidermal cells flanking the neural plate extend lamellipodia, appear to migrate over it and meet mid-dorsally. Midway in neurulation, cells near the anterior end of the neural plate begin expressing AmphiDll and, as neurulation terminates, these cells are incorporated into the dorsal part of the neural tube, which forms by a curling of the neural plate. This group of AmphiDll-expressing neural cells and a second group expressing the gene a little later and even more anteriorly in the neural tube demarcate a region that comprises the anterior three/fourths of the cerebral vesicle; this region of the amphioxus neural tube, as judged by neural expression domains of craniate Distal-less-related genes, is evidently homologous to the craniate forebrain. Our results suggest that craniates evolved from an amphioxus-like creature that had the beginnings of a forebrain and possibly a precursor of neural crest - namely, the cell population leading the epidermal overgrowth of the neural plate during early neurulation.",
    url = "https://doi.org/10.1242/dev.122.9.2911",
    doi = "10.1242/dev.122.9.2911",
    openalex = "W2189331713",
    references = "doi101086413055, doi101093nar15208125, doi101126science2204594268, doi101126science7513443, doi101242dev1092243, doi101242dev1212525, doi101242dev1213767, doi101242dev1994supplement125, doi101523jneurosci1307031551993, doi101523jneurosci1406034751994"
}

@article{anadn1998distribution,
    author = "Anad�n, Ram�n and Adrio, F�tima and Rodr�guez-moldes, Isabel",
    title = "Distribution of GABA immunoreactivity in the central and peripheral nervous system of amphioxus (Branchiostoma lanceolatum pallas)",
    year = "1998",
    journal = "The Journal of Comparative Neurology",
    url = "https://doi.org/10.1002/(sici)1096-9861(19981123)401:3<293::aid-cne1>3.0.co;2-f",
    doi = "10.1002/(sici)1096-9861(19981123)401:3<293::aid-cne1>3.0.co;2-f",
    number = "3",
    openalex = "W1976052218",
    pages = "293-307",
    volume = "401",
    references = "doi101006dbio19960034, doi101016000689938290107x, doi101016016622369090144y, doi101038377720a0, doi101098rstb19940059, doi101098rstb19960022, doi101177185315, doi101242dev1163653, doi101242dev12292911, doi101679aohc46427"
}

@article{anadón1998distribution,
    author = "Anadón, Ramón and Adrio, Fátima and Rodríguez‐moldes, Isabel",
    title = "Distribution of GABA immunoreactivity in the central and peripheral nervous system of amphioxus (Branchiostoma lanceolatum pallas)",
    year = "1998",
    journal = "The Journal of Comparative Neurology",
    url = "https://doi.org/10.1002/(sici)1096-9861(19981123)401:3<293::aid-cne1>3.3.co;2-6",
    doi = "10.1002/(sici)1096-9861(19981123)401:3<293::aid-cne1>3.3.co;2-6",
    number = "3",
    openalex = "W4236477845",
    pages = "293-307",
    volume = "401"
}

@article{doi101046j1525142x200202021x,
    author = "Boorman, Clive J. and Shimeld, Sebastian M.",
    title = "Pitx homeobox genes in Ciona and amphioxus show left–right asymmetry is a conserved chordate character and define the ascidian adenohypophysis",
    year = "2002",
    journal = "Evolution \& Development",
    abstract = "All vertebrates have directional asymmetries in the organization of their internal organs. In jawed vertebrates, development of asymmetry is controlled by a conserved molecular pathway that includes Pitx2, which is expressed by lateral plate mesoderm cells on the left side of the embryo. Pitx2 is a member of the Pitx homeobox gene family, the expression of which also marks stomodeal ectoderm and the adenohypophysis. Here we report the characterization of Pitx genes from Branchiostoma floridae (an amphioxus) and Ciona intestinalis (a urochordate), representatives of two basal chordate lineages and successively deeper outgroups to the vertebrates. Expression of B. floridae Pitx is similar to that reported from B. belcheri, a different amphioxus species. Expression of the Ciona Pitx ortholog in the embryonic primordial pharynx and adult neural complex leads us to propose the Ciona primordial pharynx and ciliated funnel are homologous to the adenohypophyseal placode and adenohypophysis, respectively. Additionally, in both species we identify asymmetrical left-sided expression of Pitx genes during embryonic development. This shows that asymmetrical Pitx gene expression, and by inference directional asymmetry, evolved before the radiation of living chordates and should be considered a chordate character.",
    url = "https://doi.org/10.1046/j.1525-142x.2002.02021.x",
    doi = "10.1046/j.1525-142x.2002.02021.x",
    openalex = "W1978591647",
    references = "doi101016s0896627300001203, doi10103829004, doi101038364334a0, doi101038527, doi101046j14697580200119910063x, doi101073pnas942413305, doi101093nar22224673, doi101093oxfordjournalsmolbeva025664, doi101242dev1243589"
}

@article{castro2003distribution,
    author = "Castro, Antonio and Manso, María Jesús and Anadón, Ramón",
    title = "Distribution of neuropeptide Y immunoreactivity in the central and peripheral nervous systems of amphioxus (Branchiostoma lanceolatum Pallas)",
    year = "2003",
    journal = "Journal of Comparative Neurology",
    abstract = "Immunocytochemistry techniques were employed to investigate the distribution of neuropeptide Y‐like‐immunoreactive (NPY‐ir) cells and fibers in the central and peripheral nervous systems of adult amphioxus. NPY‐ir neurons of the commissural type were abundant in the brain and present but more scarce in the spinal cord. These neurons gave rise to conspicuous NPY‐ir tracts that coursed along the entire length of the nerve cord. Some fibers exhibited conspicuous Herring body‐like swellings. In the peripheral nervous system, small NPY‐ir neurons and a large number of thin, beaded NPY‐ir fibers were observed in the atrial region, indicating the involvement of this substance in visceral regulation. A few NPY‐ir fibers, possibly afferent to the spinal cord, coursed in the ventral branches of the spinal nerves of this region, whereas no NPY‐ir fibers coursed in the preoral or velar nerves or in the dorsal branches of the other spinal nerves. These results indicate that NPY is widely used as a neuroregulator/neurotransmitter in the central and peripheral nervous systems of this primitive chordate. In addition, this study demonstrates the presence of tall, thin NPY‐ir cells in the putative adenohypophyseal homologue, the Hatschek's pit organ, which is located in the roof of the preoral cavity (vestibule). J. Comp. Neurol. 461:350–361, 2003. © 2003 Wiley‐Liss, Inc.",
    url = "https://doi.org/10.1002/cne.10694",
    doi = "10.1002/cne.10694",
    number = "3",
    openalex = "W1994693663",
    pages = "350-361",
    volume = "461",
    references = "doi1010160304394083904019, doi101016030645228590260x, doi1010160306452286900576, doi101038296659a0, doi101038306584a0, doi101073pnas79185485, doi101098rstb19940059, doi101126science6136091, doi101242dev12292911"
}

@article{doi101002cne10965,
    author = "Moret, Frédéric and Guilland, J.-C. and Coudouel, Sophie and Rochette, Luc and Vernier, Philippe",
    title = "Distribution of tyrosine hydroxylase, dopamine, and serotonin in the central nervous system of amphioxus (Branchiostoma lanceolatum): Implications for the evolution of catecholamine systems in vertebrates",
    year = "2003",
    journal = "The Journal of Comparative Neurology",
    abstract = "Abstract To investigate the evolutionary transition that has shaped the catecholaminergic systems of vertebrates, the organization of catecholamine‐synthesizing neurons and the nature of the catecholamines were examined in the central nervous system of adult amphioxus (Branchiostoma lanceolatum), a cephalochordate. We isolated a gene transcript encoding tyrosine hydroxylase (TH), the limiting enzyme of catecholamine biosynthesis, and studied its distribution together with that of dopamine and serotonin. Dopamine and TH are found in the same neurons of which they are three separate populations. Two are located in the anterior brain, the first being dorsal and lying in a row and the second being more posterior and lateral. A third population comprising a few dorsal commissural neurons was found in the posterior brain. The anterior dopaminergic cells innervate the ventral commissure of the cephalic vesicle, the hindbrain, and the spinal cord. A serotonin‐containing cell group is located in the same plane as the second dopaminergic cell population but is more caudal, marking the probable transition between anterior brain and hindbrain, as deduced from gene expression patterns. The overall distribution of dopaminergic and serotoninergic systems is similar in amphioxus and vertebrate central nervous system and could be an ancestral character of chordates. As assayed by high‐performance liquid chromatrography and electrochemical detection, significant amounts of dopamine and octopamine, but not of noradrenaline, are present in amphioxus head. This finding is consistent with data obtained from most prostomian species. We conclude that the noradrenergic system is probably an innovation of vertebrates that appeared along with the neural crest and specific hindbrain nuclei. J. Comp. Neurol. 468:135–150, 2004. © 2003 Wiley‐Liss, Inc.",
    url = "https://doi.org/10.1002/cne.10965",
    doi = "10.1002/cne.10965",
    openalex = "W2005407512",
    references = "castro2003distribution"
}

@article{doi101002jezb20025,
    author = "Fuentès, Michaël and Schubert, Michael and Dalfó, Diana and Candiani, Simona and Benito‐Gutiérrez, Èlia and Gardenyes, Josep and Godoy, Laura and Moret, Frédéric and Illas, Margarita and Patten, Iain and Permanyer, Jon and Oliveri, Diana and Bœuf, Gilles and Falcón, Jack and Pestarino, Mario and Fernandez, Jordi Garcia and Albalat, Ricard and Laudet, Vincent and Vernier, Philippe and Escrivá, Héctor",
    title = "Preliminary observations on the spawning conditions of the European amphioxus (Branchiostoma lanceolatum) in captivity",
    year = "2004",
    journal = "Journal of Experimental Zoology Part B Molecular and Developmental Evolution",
    abstract = "Members of the subphylum Cephalochordata, which include the genus Branchiostoma (i.e. amphioxus), represent the closest living invertebrate relatives of the vertebrates. To date, developmental studies have been carried out on three amphioxus species (the European Branchiostoma lanceolatum, the East Asian B. belcheri, and Floridian-Caribbean B. floridae). In most instances, adult animals have been collected from the field during their ripe season and allowed (or stimulated) to spawn in the laboratory. In any given year, dates of laboratory pawning have been limited by two factors. First, natural populations of these three most studied species of amphioxus are ripe, at most, for only a couple of months each year and, second, even when apparently ripe, animals spawn only at unpredictable intervals of every several days. This limited supply of living material hinders the development of amphioxus as a model system because this limitation makes it more difficult to work out protocols for new laboratory techniques. Therefore we are developing laboratory methods for increasing the number of amphioxus spawning dates per year. The present study found that a Mediterranean population of B. lanceolatum living near the Franco-Spanish border spawned naturally at the end of May and again at the end of June in 2003. Re-feeding experiments in the laboratory demonstrated that the gonads emptied at the end of May refilled with gametes by the end of June. We also found that animals with large gonads (both, obtained from the field and kept and fed at the laboratory during several weeks) could be induced to spawn in the laboratory out of phase with the field population if they were temperature shocked (spawning occurred 36 hours after a sustained increase in water temperature from 19 degrees C to 25 degrees C).",
    url = "https://doi.org/10.1002/jez.b.20025",
    doi = "10.1002/jez.b.20025",
    openalex = "W2223682499",
    references = "doi101242jcss231123445, doi1023073227024, doi105962bhltitle140340"
}

@misc{crossref2005amphioxus,
    title = "Amphioxus",
    year = "2005",
    booktitle = "Van Nostrand's Scientific Encyclopedia",
    url = "https://doi.org/10.1002/0471743984.vse0381",
    doi = "10.1002/0471743984.vse0381"
}

@article{doi101139z04163,
    author = "Wicht, Helmut and Lacalli, Thurston C.",
    title = "The nervous system of amphioxus: structure, development, and evolutionary significance",
    year = "2005",
    journal = "Canadian Journal of Zoology",
    abstract = "Amphioxus neuroanatomy is important not just in its own right but also for the insights it provides regarding the evolutionary origin and basic organization of the vertebrate nervous system. This review summarizes the overall layout of the central nervous system (CNS), peripheral nerves, and nerve plexuses in amphioxus, and what is currently known of their histology and cell types, with special attention to new information on the anterior nerve cord. The intercalated region (IR) is of special functional and evolutionary interest. It extends caudally to the end of somite 4, traditionally considered the limit of the brain-like region of the amphioxus CNS, and is notable for the presence of a number of migrated cell groups. Unlike most other neurons in the cord, these migrated cells detach from the ventricular lumen and move into the adjacent neuropile, much as developing neurons do in vertebrates. The larval nervous system is also considered, as there is a wealth of new data on the organization and cell types of the anterior nerve cord in young larvae, based on detailed electron microscopical analyses and nerve tracing studies, and an emerging consensus regarding how this region relates to the vertebrate brain. Much less is known about the intervening period of the life history, i.e., the period between the young larva and the adult, but a great deal of neural development must occur during this time to generate a fully mature nervous system. It is especially interesting that the vertebrate counterparts of at least some postembryonic events of amphioxus neurogenesis occur, in vertebrates, in the embryo. The implication is that the whole of the postembryonic phase of neural development in amphioxus needs to be considered when making phylogenetic comparisons. Yet this is a period about which almost nothing is known. Considering this, plus the number of new molecular and immunocytochemical techniques now available to researchers, there is no shortage of worthwhile research topics using amphioxus, of whatever stage, as a subject.",
    url = "https://doi.org/10.1139/z04-163",
    doi = "10.1139/z04-163",
    openalex = "W2092757339",
    references = "anadn1998distribution, bone1959the, bone1961the, castro2003distribution, dogiel1903das, doi101002cne901150105, doi101002jmor1050540103, doi1010079783642182624, doi101007bf00348527, doi101007bf02028391, doi101016jydbio200604457, doi101016s0022532062800070, doi101098rstb19940059, doi101098rstb19960022, doi101111j146363951995tb00986x, doi101139z04160, doi101159000079744, doi101159000147530, doi101242dev125142701, doi101242jcss310052509, doi1023071535762, doi103166jds1391111, doi105962bhltitle159385, doi105962bhltitle55924, flood1974histochemistry, holmes1953the, openalexw2394638245, openalexw659399033, ruiz1991the, stokes1995ciliary"
}

@article{doi101016jydbio200604457,
    author = "Schubert, Michael and Holland, Nicholas D. and Laudet, Vincent and Holland, Linda Z.",
    title = "A retinoic acid-Hox hierarchy controls both anterior/posterior patterning and neuronal specification in the developing central nervous system of the cephalochordate amphioxus",
    year = "2006",
    journal = "Developmental Biology",
    url = "https://doi.org/10.1016/j.ydbio.2006.04.457",
    doi = "10.1016/j.ydbio.2006.04.457",
    openalex = "W2038167511",
    references = "doi101006dbio20009630, doi101016s0091679x04740091, doi101111j146363951995tb00986x, doi101139z04163, doi101242dev12661295"
}

@article{daniello2007nmethyldaspartic,
    author = "D'Aniello, Salvatore and Fisher, George H and Topo, Enza and Ferrandino, Gabriele and Garcia-Fernàndez, Jordi and D'Aniello, Antimo",
    title = "N-Methyl-D-aspartic Acid (NMDA) in the nervous system of the amphioxus Branchiostoma lanceolatum",
    year = "2007",
    journal = "BMC Neuroscience",
    url = "https://doi.org/10.1186/1471-2202-8-109",
    doi = "10.1186/1471-2202-8-109",
    number = "1",
    openalex = "W2074214146",
    volume = "8",
    references = "doi101002jezb21179, doi101016030504919390113j, doi101016s0301008200000678, doi101038nature04336, doi101042bj2410309, doi101096fasebj145699, doi101146annurevne17030194000335, doi101210en141103862, doi101210endo12062289, doi101210endo141107706"
}

@article{doi101002jezb21179,
    author = "Fuentès, Michaël and Benito‐Gutiérrez, Èlia and Bertrand, Stéphanie and Paris, Mathilde and Mignardot, Aurelie and Godoy, Laura and Jiménez‐Delgado, Senda and Oliveri, Diana and Candiani, Simona and Hirsinger, Estelle and D’Aniello, Salvatore and Pascual‐Anaya, Juan and Maeso, Ignacio and Pestarino, Mario and Vernier, Philippe and Nicolas, Jean‐François and Schubert, Michael and Laudet, Vincent and Genevière, Anne Marie and Albalat, Ricard and García‐Fernàndez, Jordi and Holland, Nicholas D. and Escrivá, Héctor",
    title = "Insights into spawning behavior and development of the european amphioxus (Branchiostoma lanceolatum)",
    year = "2007",
    journal = "Journal of Experimental Zoology Part B Molecular and Developmental Evolution",
    abstract = "The cephalochordate amphioxus (Branchiostoma sp.) is an important animal model for studying the evolution of chordate developmental mechanisms. Obtaining amphioxus embryos is a key step for these studies. It has been shown that an increase of 3-4 degrees C in water temperature triggers spawning of the European amphioxus (Branchiostoma lanceolatum) in captivity, however, very little is known about the natural spawning behavior of this species in the field. In this work, we have followed the spawning behavior of the European amphioxus during two spawning seasons (2004 and 2005), both in the field and in captivity. We show that animals in the field spawn approximately from mid-May through early July, but depending on the year, they show different patterns of spawning. Thus, even if temperature has a critical role in the induction of the spawning in captivity, it is not the major factor in the field. Moreover, we report some improvements on the methodology for inducing spawning in captivity (e.g. in maintenance, light cycle control and induction of spawning in a laboratory without running sea water system). These studies have important implications for amphioxus animal husbandry and for improving laboratory techniques to develop amphioxus as an experimental animal model.",
    url = "https://doi.org/10.1002/jez.b.21179",
    doi = "10.1002/jez.b.21179",
    openalex = "W2021013626",
    references = "doi101016s0091679x04740091, doi1023073227024"
}

@article{doi101101gr073676107,
    author = "Holland, Linda Z. and Albalat, Ricard and Azumi, Kaoru and Benito‐Gutiérrez, Èlia and Blow, Matthew J. and Bronner‐Fraser, Marianne and Brunet, Frédéric and Butts, Thomas and Candiani, Simona and Dishaw, Larry J. and Ferrier, David and García‐Fernàndez, Jordi and Gibson‐Brown, Jeremy J. and Gissi, Carmela and Godzik, Adam and Hallböök, Finn and Hirose, Dan and Hosomichi, Kazuyoshi and Ikuta, Tetsuro and Inoko, Hidetoshi and Kasahara, Masanori and Kasamatsu, Jun and Kawashima, Takeshi and Kimura, Ayuko and Kobayashi, Masaaki and Kozmík, Zbyněk and Kubokawa, Kaoru and Laudet, Vincent and Litman, Gary W. and McHardy, Alice C. and Meulemans, Daniel and Nonaka, Masaru and Olinski, Robert P. and Pancer, Zeev and Pennacchio, L and Pestarino, Mario and Rast, Jonathan P. and Rigoutsos, Isidore and Robinson‐Rechavi, Marc and Roch, Graeme J. and Saiga, Hidetoshi and Sasakura, Yasunori and Satake, Masanobu and Satou, Yutaka and Schubert, Michael and Sherwood, Nancy M. and Shiina, Takashi and Takatori, Naohito and Tello, Javier A. and Vopálenský, Pavel and Wada, Shuichi and Xu, Anlong and Ye, Yuzhen and Yoshida, Keita and Yoshizaki, Fumiko and Yu, J-R and Zhang, Qing and Zmasek, Christian M. and de Jong, Pieter J. and Osoegawa, Kazutoyo and Putnam, Nicholas H. and Rokhsar, Daniel S. and Satoh, Noriyuki and Holland, Peter W. H.",
    title = "The amphioxus genome illuminates vertebrate origins and cephalochordate biology",
    year = "2008",
    journal = "Genome Research",
    abstract = "Cephalochordates, urochordates, and vertebrates evolved from a common ancestor over 520 million years ago. To improve our understanding of chordate evolution and the origin of vertebrates, we intensively searched for particular genes, gene families, and conserved noncoding elements in the sequenced genome of the cephalochordate Branchiostoma floridae, commonly called amphioxus or lancelets. Special attention was given to homeobox genes, opsin genes, genes involved in neural crest development, nuclear receptor genes, genes encoding components of the endocrine and immune systems, and conserved cis-regulatory enhancers. The amphioxus genome contains a basic set of chordate genes involved in development and cell signaling, including a fifteenth Hox gene. This set includes many genes that were co-opted in vertebrates for new roles in neural crest development and adaptive immunity. However, where amphioxus has a single gene, vertebrates often have two, three, or four paralogs derived from two whole-genome duplication events. In addition, several transcriptional enhancers are conserved between amphioxus and vertebrates--a very wide phylogenetic distance. In contrast, urochordate genomes have lost many genes, including a diversity of homeobox families and genes involved in steroid hormone function. The amphioxus genome also exhibits derived features, including duplications of opsins and genes proposed to function in innate immunity and endocrine systems. Our results indicate that the amphioxus genome is elemental to an understanding of the biology and evolution of nonchordate deuterostomes, invertebrate chordates, and vertebrates.",
    url = "https://doi.org/10.1101/gr.073676.107",
    doi = "10.1101/gr.073676.107",
    openalex = "W2135740919",
    references = "doi10103835057062, doi101038nature01262, doi101038nature03025, doi101038nature04072, doi101038nature05260, doi101093nargkh458, doi101126science1058040, doi101126science28253962012, doi101126science28754612185, openalexw2981209166"
}

@article{doi101186147122021359,
    author = "Candiani, Simona and Moronti, Luca and Ramoino, Paola and Schubert, Michael and Pestarino, Mario",
    title = "A neurochemical map of the developing amphioxus nervous system",
    year = "2012",
    journal = "BMC Neuroscience",
    abstract = "In this study, we assessed neuronal differentiation in the developing amphioxus nervous system and compiled the first neurochemical map of the amphioxus CNS. This map is a first step towards a full characterization of the neurotransmitter signature of previously described nerve cell types in the amphioxus CNS, such as motoneurons and interneurons.",
    url = "https://doi.org/10.1186/1471-2202-13-59",
    doi = "10.1186/1471-2202-13-59",
    openalex = "W2032092557",
    references = "anadn1998distribution, doi101016030100829190006m, doi101016s0022283605803602, doi101016s0031699725000250, doi101016s0076687996660248, doi10103835053516, doi101038nature06967, doi101093molbevmsr121, doi101152physrev1992721165, doi101523jneurosci1823097331998, openalexw2560671010"
}

@article{doi10118620419139427,
    author = "Holland, Linda Z. and Carvalho, João E. and Escrivá, Héctor and Laudet, Vincent and Schubert, Michael and Shimeld, Sebastian M. and Yu, Jr‐Kai",
    title = "Evolution of bilaterian central nervous systems: a single origin?",
    year = "2013",
    journal = "EvoDevo",
    abstract = "The question of whether the ancestral bilaterian had a central nervous system (CNS) or a diffuse ectodermal nervous system has been hotly debated. Considerable evidence supports the theory that a CNS evolved just once. However, an alternative view proposes that the chordate CNS evolved from the ectodermal nerve net of a hemichordate-like ancestral deuterostome, implying independent evolution of the CNS in chordates and protostomes. To specify morphological divisions along the anterior/posterior axis, this ancestor used gene networks homologous to those patterning three organizing centers in the vertebrate brain: the anterior neural ridge, the zona limitans intrathalamica and the isthmic organizer, and subsequent evolution of the vertebrate brain involved elaboration of these ancestral signaling centers; however, all or part of these signaling centers were lost from the CNS of invertebrate chordates. The present review analyzes the evidence for and against these theories. The bulk of the evidence indicates that a CNS evolved just once - in the ancestral bilaterian. Importantly, in both protostomes and deuterostomes, the CNS represents a portion of a generally neurogenic ectoderm that is internalized and receives and integrates inputs from sensory cells in the remainder of the ectoderm. The expression patterns of genes involved in medio/lateral (dorso/ventral) patterning of the CNS are similar in protostomes and chordates; however, these genes are not similarly expressed in the ectoderm outside the CNS. Thus, their expression is a better criterion for CNS homologs than the expression of anterior/posterior patterning genes, many of which (for example, Hox genes) are similarly expressed both in the CNS and in the remainder of the ectoderm in many bilaterians. The evidence leaves hemichordates in an ambiguous position - either CNS centralization was lost to some extent at the base of the hemichordates, or even earlier, at the base of the hemichordates + echinoderms, or one of the two hemichordate nerve cords is homologous to the CNS of protostomes and chordates. In any event, the presence of part of the genetic machinery for the anterior neural ridge, the zona limitans intrathalamica and the isthmic organizer in invertebrate chordates together with similar morphology indicates that these organizers were present, at least in part, at the base of the chordates and were probably elaborated upon in the vertebrate lineage.",
    url = "https://doi.org/10.1186/2041-9139-4-27",
    doi = "10.1186/2041-9139-4-27",
    openalex = "W2131278302",
    references = "doi101002jmor10533, doi101002jmor10868, doi101007s004270050225, doi101016jcub200905063, doi101016jgde200506004, doi101016jydbio201005016, doi101111j146363951995tb00986x, doi101111j146979981978tb03931x, doi101242dev066712, doi101242dev12661295, openalexw600124373"
}

@article{doi101002cne23785,
    author = "Castro, A. and Becerra, Manuela and Manso, Marı́a Jesús and Anadón, Ramón",
    title = "Neuronal organization of the brain in the adult amphioxus (Branchiostoma lanceolatum): A study with acetylated tubulin immunohistochemistry",
    year = "2015",
    journal = "The Journal of Comparative Neurology",
    abstract = "Amphioxus (Cephalochordata) belongs to the most basal extant chordates, and knowledge of their brain organization appears to be key to deciphering the early stages of evolution of vertebrate brains. Most comprehensive studies of the organization of the central nervous system of adult amphioxus have investigated the spinal cord. Some brain populations have been characterized via neurochemistry and electron microscopy, and the overall cytoarchitecture of the brain was studied by Ekhart et al. (2003; J. Comp. Neurol. 466:319-330) with general staining methods and retrograde transport from the spinal cord. Here, the cytoarchitecture of the brain of adult amphioxus Branchiostoma lanceolatum was reinvestigated by using acetylated tubulin immunohistochemistry, which specifically stains neurons and fibers, in combination with some ancillary methods. This method allowed reproducible staining and mapping of types of neuron, mostly in brain regions caudal to the entrance level of nerve 2, and its comparison with spinal cord populations. The brain populations studied and discussed in detail were the Retzius bipolar cells, lamellate cells, Joseph cells, various types of translumenal cells, somatic motoneurons, Rohde nucleus cells, small ventral multipolar neurons, and Edinger cells. These observations expand our knowledge of the distribution of cell types and provide additional data on the number of cells and the axonal tracts and commissural regions of the adult amphioxus brain. The results of this comprehensive study provide a framework for comparison of complex adult populations with the early brain neuronal populations revealed in developmental studies of the amphioxus.",
    url = "https://doi.org/10.1002/cne.23785",
    doi = "10.1002/cne.23785",
    openalex = "W1882862961",
    references = "castro2003distribution, doi101007bf00348527, doi101007bf02028391, doi101007bf02933895, doi101387ijdb072436jg, holmes1953the, openalexw2394638245"
}

@article{doi101074jbcm115664003,
    author = "Sekiguchi, Toshio and Kuwasako, Kenji and Ogasawara, Michio and Takahashi, Hiroki and Matsubara, Shin and Osugi, Tomohiro and Muramatsu, Ikunobu and Sasayama, Yuichi and Suzuki, Nobuo and Satake, Honoo",
    title = "Evidence for Conservation of the Calcitonin Superfamily and Activity-regulating Mechanisms in the Basal Chordate Branchiostoma floridae: INSIGHTS INTO THE MOLECULAR AND FUNCTIONAL EVOLUTION IN CHORDATES.",
    year = "2016",
    journal = "The Journal of biological chemistry",
    abstract = "The calcitonin (CT)/CT gene-related peptide (CGRP) family is conserved in vertebrates. The activities of this peptide family are regulated by a combination of two receptors, namely the calcitonin receptor (CTR) and the CTR-like receptor (CLR), and three receptor activity-modifying proteins (RAMPs). Furthermore, RAMPs act as escort proteins by translocating CLR to the cell membrane. Recently, CT/CGRP family peptides have been identified or inferred in several invertebrates. However, the molecular characteristics and relevant functions of the CTR/CLR and RAMPs in invertebrates remain unclear. In this study, we identified three CT/CGRP family peptides (Bf-CTFPs), one CTR/CLR-like receptor (Bf-CTFP-R), and three RAMP-like proteins (Bf-RAMP-LPs) in the basal chordate amphioxus (Branchiostoma floridae). The Bf-CTFPs were shown to possess an N-terminal circular region typical of the CT/CGRP family and a C-terminal Pro-NH2. The Bf-CTFP genes were expressed in the central nervous system and in endocrine cells of the midgut, indicating that Bf-CTFPs serve as brain and/or gut peptides. Cell surface expression of the Bf-CTFP-R was enhanced by co-expression with each Bf-RAMP-LP. Furthermore, Bf-CTFPs activated Bf-CTFP-R·Bf-RAMP-LP complexes, resulting in cAMP accumulation. These results confirmed that Bf-RAMP-LPs, like vertebrate RAMPs, are prerequisites for the function and translocation of the Bf-CTFP-R. The relative potencies of the three peptides at each receptor were similar. Bf-CTFP2 was a potent ligand at all receptors in cAMP assays. Bf-RAMP-LP effects on ligand potency order were distinct to vertebrate CGRP/adrenomedullin/amylin receptors. To the best of our knowledge, this is the first molecular and functional characterization of an authentic invertebrate CT/CGRP family receptor and RAMPs.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC4732217/",
    doi = "10.1074/jbc.M115.664003",
    openalex = "W2292273288",
    pmcid = "PMC4732217",
    pmid = "26644465",
    references = "doi101006bbrc19931451, doi1010160378111988903307, doi101038298240a0, doi101038304129a0, doi10103830666, doi101038nature04336, doi101038nature06967, doi101093molbevmsm092, doi101093nargkt381, doi101093oxfordjournalsmolbeva040454"
}

@article{doi101126sciadvadq0702,
    author = "Dai, Yichen and Pan, Rongrong and Pan, Qi and Wu, Xiaotong and Cai, Zexin and Fu, Yongheng and Shi, Chenggang and Sheng, Yizhe and Li, Jingjing and Lin, Zhe and Liu, Gaoming and Zhu, Pingfen and Li, Meng and Li, Guang and Zhou, Xuming",
    title = "Single-cell profiling of the amphioxus digestive tract reveals conservation of endocrine cells in chordates",
    year = "2024",
    journal = "Science Advances",
    abstract = "Despite their pivotal role, the evolutionary origins of vertebrate digestive systems remain enigmatic. We explored the cellular characteristics of the amphioxus (Branchiostoma floridae) digestive tract, a model for the presumed primitive chordate digestive system, using bulk tissue companioned with single-cell RNA sequencing. Our findings reveal segmentation and a rich diversity of cell clusters, and we highlight the presence of epithelial-like, ciliated cells in the amphioxus midgut and describe three types of endocrine-like cells that secrete insulin-like, glucagon-like, and somatostatin-like peptides. Furthermore, Pdx, Ilp1, Ilp2, and Ilpr knockout amphioxus lines revealed that, in amphioxus, Pdx does not influence Ilp expression. We also unravel similarity between amphioxus Ilp1 and vertebrate insulin-like growth factor 1 (Igf1) in terms of predicted structure, effects on body growth and amino acid metabolism, and interactions with Igf-binding proteins. These findings indicate that the evolutionary alterations involving the regulatory influence of Pdx over insulin gene expression could have been instrumental in the development of the vertebrate digestive system.",
    url = "https://doi.org/10.1126/sciadv.adq0702",
    doi = "10.1126/sciadv.adq0702",
    openalex = "W4405632874",
    references = "doi101007s00441019030355, doi101074jbcm115664003, doi101387ijdb170196nh"
}

@article{doi101016jdci2026105550,
    author = "Liang, Bangyao and Meng, Wei and Chen, Meihan and Miao, Hongfei and Ren, Yuhan and Liu, Hongyu and Liu, Zhenhui and Sun, Chen",
    title = "Peroxiredoxin 4 from amphioxus: An antioxidant enzyme with immunomodulatory roles in defense against Vibrio anguillarum.",
    year = "2026",
    journal = "Developmental and comparative immunology",
    abstract = "Peroxiredoxin 4 (Prdx4), a typical 2-Cys peroxiredoxin, functions as both an antioxidant enzyme and a regulator of immune processes, yet its roles in early chordates remain unclear. Here, we identified and characterized a Prdx4 homolog from amphioxus (Branchiostoma japonicum), termed BjPrdx4. Sequence analyses revealed conserved catalytic motifs and an N-terminal signal peptide, supporting its classification as Prdx4. BjPrdx4 was constitutively expressed across multiple tissues, with prominent localization in immune-associated tissues, and its expression was markedly induced following Vibrio anguillarum challenge. Infection also triggered BjPrdx4 secretion into the extracellular milieu and altered its oligomeric states. Recombinant BjPrdx4 exhibited robust thiol-dependent peroxidase activity, efficiently eliminating hydrogen peroxide and protecting plasmid DNA from oxidative damage, confirming its antioxidant function. Functionally, extracellular BjPrdx4 preserved gill integrity and reduced bacterial burden during infection. Transcriptomic and qRT-PCR analyses further demonstrated that BjPrdx4 influenced immune-related pathways, including phagocytosis and lysosomal activity, and positively regulated ras expression, suggesting involvement in Ras-MAPK signaling. Together, these findings reveal that BjPrdx4 integrates antioxidant defense with immunomodulatory functions, highlighting its dual role in amphioxus antibacterial immunity and underscoring the evolutionary significance of Prdx4 multifunctionality in basal chordates.",
    url = "https://pubmed.ncbi.nlm.nih.gov/41506560/",
    doi = "10.1016/j.dci.2026.105550",
    pmid = "41506560",
    references = "doi101007978331976768016"
}

@article{doi101016jmolimm202603009,
    author = "Gao, Jing and Kang, Haowu and Wang, Lu and Wang, Haitao and Gao, Zhan",
    title = "A functional VCBP-C1q interaction in amphioxus reveals evolutionary origins of the classical complement pathway.",
    year = "2026",
    journal = "Molecular immunology",
    abstract = "The origin of the classical complement pathway remains unclear, primarily due to the evolutionary interplay between immunoglobulin (Ig) and C1q. An Ig superfamily member, variable region-containing chitin-binding protein 5 (VCBP5), from the basal chordate amphioxus exhibited a marked upregulation upon E. coli stimulation and accumulated in the epithelial lining and circulatory sinuses of the hepatic caecum. Recombinant VCBP5 (rVCBP5) exhibits strong binding affinity for E. coli via the C'C'' loop of its IgV2 domain. Exogenous addition of rVCBP5 not only enhances the bactericidal activity of humoral fluids but also provides robust protection against bacterial proliferation in vivo. Notably, rVCBP5 specifically binds to the gC1q domain of BjC1q, with the interdomain hinge regions of VCBP5 serving as key interaction interfaces. Moreover, rBjC1q directly interacts with the serine protease BjMASP1/3. Importantly, formation of the VCBP5-bacterial complex facilitates rBjC1q-mediated recruitment of BjMASP1/3, thereby triggering complement activation. Our findings uncover a functional VCBP-C1q partnership in amphioxus, revealing a primitive complement activation pathway. This discovery provides new insights into the evolutionary emergence of the classical complement pathway.",
    url = "https://pubmed.ncbi.nlm.nih.gov/41934766/",
    doi = "10.1016/j.molimm.2026.03.009",
    pmid = "41934766"
}

@article{doi101073pnas2521280123,
    author = "Ren, Yifan and Miao, Zepu and Lin, Che-Yi and Yang, Ludong and Li, Huihui and Holland, Linda Z and Cho, Sung-Jin and Yu, Jr-Kai and Yue, Jia-Xing",
    title = "Insights into cephalochordate genome and gene evolution from the early-diverging amphioxus Asymmetron lucayanum.",
    year = "2026",
    journal = "Proceedings of the National Academy of Sciences of the United States of America",
    abstract = "Cephalochordates (amphioxus or lancelet) are considered as living proxies for ancestral chordates due to their key phylogenetic position and slow evolutionary rate. The genomes of living amphioxus thus can help to reveal the genetic basis shaping the evolutionary transition from nonvertebrate animals to vertebrates. To gain a comprehensive understanding of the genome architecture in amphioxus, we generated a chromosome-anchored genome assembly for Asymmetron lucayanum, representing the earliest diverging cephalochordate genus. We show that Asymmetron has an enlarged genome compared to those of the other four cephalochordate genomes decoded so far (all in the genus Branchiostoma), caused by pervasive expansions of intergenic transposable elements (TEs). Nevertheless, both macrosynteny and microsynteny remain highly conserved between Asymmetron and Branchiostoma, enabling reconstruction of the ancestral genomic architecture of the cephalochordate lineage for tracing genome evolutionary processes during deuterostome and chordate diversification. Integration of developmental transcriptomic data further reveals that selective constraints on cotranscriptional regulation underline the maintenance of the conserved microsynteny blocks among cephalochordate species. We also examine the evolutionary history of the Hox cluster in cephalochordates and vertebrates, and identify species-specific inversions and TE invasions at this locus in both Asymmetron and Branchiostoma. Finally, we survey key molecular building blocks underlying both innate and adaptive immunity (e.g., TLR, NLR, MHC, and RAG) and uncover their evolutionary dynamics and plausible ancestry in chordates. Taken together, our findings illuminate the genome and gene evolution of cephalochordates and provide valuable resources for understanding the early evolution of chordates and the origin of vertebrates.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC13012124/",
    doi = "10.1073/pnas.2521280123",
    pmcid = "PMC13012124",
    pmid = "41860958",
    references = "doi101016jmargen201503010"
}

@article{doi101093jmcbmjag009,
    author = "Xu, Jie and Hu, Haikun and Lu, Qingyi and Wei, Qiuzhu and Zhang, Yuhang and Huang, Guangrui and Xu, Anlong",
    title = "Amphioxus tyrosine kinase SYK inhibits NF-κB activation through MyD88-dependent mechanism.",
    year = "2026",
    journal = "Journal of molecular cell biology",
    abstract = "The spleen tyrosine kinase (SYK) plays pivotal roles in the adaptive immune response by recognizing phosphorylated immunoreceptor tyrosine-based activation motif (ITAM) and activating downstream effectors. However, the emergence of SYK predates the advent of adaptive immunity, and its original functions independent of the adaptive immune system remain largely unknown. In this study, we identified and characterized a SYK homolog (bjSYK) in the amphioxus Branchiostoma japonicum, a key model for understanding immune system evolution. Phylogenetic analysis positioned bjSYK basally among deuterostome SYK kinases. Expression analysis revealed its localization in immune-relevant tissues. Contrary to the canonical activating role in vertebrates, functional studies demonstrated that bjSYK acts as a potent suppressor of NF-κB activation. Specifically, bjSYK directly interacts with bjMyD88 via its SH2 domains binding to a conserved hemi-ITAM motif, suppressing K63-linked polyubiquitination of bjMyD88 and consequently inhibiting bjMyD88-dependent NF-κB signaling. Furthermore, bjSYK also suppresses NF-κB activation through bjTRAF6, a key adaptor downstream of bjMyD88, by inhibiting its ubiquitination. These findings reveal an evolutionarily ancient inhibitory role of bjSYK in NF-κB signaling in basal chordate innate immunity, suggesting that SYK-mediated negative regulation of Toll-like receptor pathways originates in amphioxus and provides a foundation for the context-dependent functions of SYK in vertebrate immunity.",
    url = "https://pubmed.ncbi.nlm.nih.gov/41837541/",
    doi = "10.1093/jmcb/mjag009",
    pmid = "41837541"
}

@article{doi101093molbevmsag017,
    author = "Xue, Jing and Tao, Lei and Cao, Junwei and Wu, Liang and Li, Guang and Li, Cai",
    title = "Germline de novo mutation rate of the highly heterozygous amphioxus genome.",
    year = "2026",
    journal = "Molecular biology and evolution",
    abstract = "Germline de novo mutations (DNMs) are the ultimate source of heritable variation, yet their patterns in highly heterozygous genomes remain poorly understood. Amphioxus, an early-branching chordate with exceptionally high genomic heterozygosity (3.2\% to 4.2\% in sequenced species), offers a unique model to explore mutational dynamics in such contexts. It is unclear whether high heterozygosity in amphioxus is due to a large effective population size, an increased mutation rate, or both. Here, we perform deep short-read whole-genome sequencing of a two-generation pedigree of the amphioxus Branchiostoma floridae comprising two parents and 104 offspring and develop a framework based on allele-aware parental assemblies as the reference to accurately identify DNMs. We detect 242 high-confidence DNMs, yielding a genome-wide mutation rate of 5.89 × 10-9 per base per generation, which is comparable to that of vertebrates. Combining this estimate with observed nucleotide diversity, we obtain an effective population size of ∼1.7 million, indicating that the elevated heterozygosity mainly results from a large effective population size. We observe no sex bias when considering all DNMs but a paternal-origin bias for early-occurring ones. Amphioxus harbors a much smaller fraction of CpG>TpG DNMs relative to vertebrates, attributable to its low methylation levels. We also investigate putative postzygotic mutations in the offspring, revealing an unexpected paternal-origin bias. These suggest some distinct mutational mechanisms in amphioxus. Our study not only provides the first DNM measurement for amphioxus but also offers a generalizable strategy for studying DNMs in highly heterozygous genomes, facilitating mutation rate studies across chordates and other lineages.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC12862219/",
    doi = "10.1093/molbev/msag017",
    pmcid = "PMC12862219",
    pmid = "41530943",
    references = "doi10115520203697342"
}