| 1. |
- Fritzsch, Guido, et al.
(författare)
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PCR Survey of Xenoturbella bocki Hox Genes
- 2008
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Ingår i: JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL). - : Wiley. ; 310B:3, s. 278-284
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Tidskriftsartikel (refereegranskat)abstract
- Xenoturbella bocki has recently been identified as one of the most basal deuterostomes, although an even more basal phylogenetic position cannot be ruled out. Here we report on a polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki. Surprisingly, we did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open. We furthermore report on a re-evaluation of the available published evidence of Hox genes in other basal deuterostomes.
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| 2. |
- Rosenberg, Rutger, 1943, et al.
(författare)
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Biology of the basket star Gorgonocephalus caputmedusae (L.)
- 2005
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Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 148, s. 43-50
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Tidskriftsartikel (refereegranskat)abstract
- Ophiurid basket stars belonging to the family Gorgonocephalidae are distributed from the Arctic to the Antarctic and from the shallow subtidal to the deep sea, but their biology remains poorly known. In situ observations at the mouth of the Oslofjord by a remotely operated vehicle showed that Gorgonocephalus caputmedusae had a patchy distribution at 85 to 120 m water depth and frequently occurred in association with the gorgonian Paramuricea placomus and the coral Lophelia pertusa. Morphological and histological studies show that G. caputmedusae is well adapted to capture macroplanktonic prey. Histological examination of the arms revealed the presence of a thick layer of dermal mutable connective tissue which is probably an energyefficient way to maintain its feeding posture against the current. This layer is connected to the nerve cord suggesting that the passive mechanical properties (stiffness) is controlled by the nervous system. In the distal parts of the arms, each segment has a pair of sticky tube feet and a sophisticated system of spines and hooks, which are connected to muscles and collagenous tendons. In combination, these features were shown, in an experimental flume study, to be used for capturing the locally abundant krill species Meganyctiphanes norvegica. This is the first documentation of G. caputmedusae of this kind
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| 3. |
- Stach, Thomas, et al.
(författare)
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Nerve cells of Xenoturbella bocki (phylum uncertain) and Harrimania kupfferi (Enteropneusta) are positively immunoreactive to antibodies raised against echinoderm neuropeptides
- 2005
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Ingår i: Journal of the Marine Biological Association of the UK. ; 85:6, s. 1519-1524
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic position of Xenoturbella spp. has been uncertain since their discovery in 1949. It has been recently suggested that they could be related to Ambulacraria within Deuterostomia. Ambulacraria is a taxon that has been suggested to consist of Hemichordata and Echinodermata. The hypothesis that X. bocki was related to Ambulacraria as well as the hypothesis of a monophyletic Ambulacraria is primarily based on the analysis of DNA sequence data. We tested both phylogenetic hypotheses using antibodies raised against SALMFamide 1 and 2 (S1, S2), neuropeptides isolated from echinoderms, on X. bocki and the enteropneust Harrimania kupfferi. Both species showed distinct positive immunoreactivity against S1 and S2. This finding supports the Ambulacraria-hypothesis and suggests a close phylogenetic relationship of X. bocki to Ambulacraria. In particular, the presence of immunoreactivity against S2 can be interpreted as a synapomorphy of Enteropneusta, Echinodermata, and Xenoturbella spp
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| 4. |
- Stach, Thomas, et al.
(författare)
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Nerve cells of Xenoturbella bocki (phylum uncertain) and Harrimania kupfferi (Enteropneusta) are positively immunoreactive to antibodies raised against echinoderm neuropeptides
- 2005
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - : Cambridge University Press. - 0025-3154 .- 1469-7769. ; 85:6, s. 1519-1524
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Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic position of Xenoturbella spp. has been uncertain since their discovery in 1949. It has been recently suggested that they could be related to Ambulacraria within Deuterostomia. Ambulacraria is a taxon that has been suggested to consist of Hemichordata and Echinodermata. The hypothesis that X. bocki was related to Ambulacraria as well as the hypothesis of a monophyletic Ambulacraria is primarily based on the analysis of DNA sequence data. We tested both phylogenetic hypotheses using antibodies raised against SALMFamide 1 and 2 (S1, S2), neuropeptides isolated from echinoderms, on X. bocki and the enteropneust Harrimania kupfferi. Both species showed distinct positive immunoreactivity against S1 and S2. This finding supports the Ambulacraria-hypothesis and suggests a close phylogenetic relationship of X. bocki to Ambulacraria. In particular, the presence of immunoreactivity against S2 can be interpreted as a synapomorphy of Enteropneusta, Echinodermata, and Xenoturbella spp.
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