| 1. |
- Delroisse, J., et al.
(författare)
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A puzzling homology: a brittle star using a putative cnidarian-type luciferase for bioluminescence
- 2017
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Ingår i: Open Biology. - : The Royal Society. - 2046-2441. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Bioluminescence relies on the oxidation of a luciferin substrate catalysed by a luciferase enzyme. Luciferins and luciferases are generic terms used to describe a large variety of substrates and enzymes. Whereas luciferins can be shared by phylogenetically distant organisms which feed on organisms producing them, luciferases have been thought to be lineage-specific enzymes. Numerous light emission systems would then have co-emerged independently along the tree of life resulting in a plethora of non-homologous luciferases. Here, we identify for the first time a candidate luciferase of a luminous echinoderm, the ophiuroid Amphiura filiformis. Phylogenomic analyses identified the brittle star predicted luciferase as homologous to the luciferase of the sea pansy Renilla (Cnidaria), contradicting with the traditional viewpoint according to which luciferases would generally be of convergent origins. The similarity between the Renilla and Amphiura luciferases allowed us to detect the latter using anti-Renilla luciferase antibodies. Luciferase expression was specifically localized in the spines which were demonstrated to be the bioluminescent organs in vivo. However, enzymes homologous to the Renilla luciferase but unable to trigger light emission were also identified in non-luminous echinoderms and metazoans. Our findings strongly indicate that those enzymes, belonging to the haloalkane dehalogenase family, might then have been convergently co-opted into luciferases in cnidarians and echinoderms. In these two benthic suspension-feeding species, similar ecological pressures would constitute strong selective forces for the functional shift of these enzymes and the emergence of bioluminescence.
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| 2. |
- Delroisse, J., et al.
(författare)
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De novo transcriptome of the European brittle star Amphiura filiformis pluteus larvae
- 2015
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Ingår i: Marine Genomics. - : Elsevier. - 1874-7787. ; 23, s. 109-121
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Tidskriftsartikel (refereegranskat)abstract
- Background: In non-classical model species, Next Generation Sequencing increases the ability to analyze the expression of transcripts/genes. In this study, paired-end Illumina HiSeq sequencing technology has been employed to describe a larval transcriptome generated from 64 h post-fertilization pluteus larvae of the brittle star Amphiura filiformis. We focused our analysis on the detection of actors involved in the opsin based light perception, respectively the opsins and the phototransduction actors. Methods & results: In this research, about 47 million high quality readswere generated and 86,572 total unigenes were predicted after de novo assembly. Of all the larval unigenes, 18% show significant matches with reference online databases. 46% of annotated larval unigenes were significantly similar to transcripts from the purple sea urchin. COG, GO and KEGG analyses were performed on predicted unigenes. Regarding the opsin-based photoreception process, even if possible actors of ciliary and rhabdomeric phototransduction cascadeswere detected, no ciliary or rhabdomeric opsinwas identified in these larvae. Additionally, partial non-visual RGR (retinal G protein coupled receptor) opsin mRNAs were identified,possibly indicating the presence of visual cycle reaction in early pluteus larvae. The eye morphogene Pax 6 was also identified in the pluteus transcriptome. Conclusions: Contrary to sea-urchin larvae, brittle star larvae appear to be characterized by an absence of visuallike opsins. These RNA-seq data also provide a useful resource for the echinoderm research community and researchers with an interest in larval biology. © 2015 Elsevier B.V.
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| 3. |
- Delroisse, J, et al.
(författare)
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Opsin-based extraocular photoreception in a luminous brittle star
- 2014
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Ingår i: Luminescence. Special Issue: Abstracts of the 18th International Symposium on Bioluminescence and Chemiluminescence, June 23–28 2014, Uppsala, Sweden (ISBC 2014). - 1522-7235. ; 29:S1, s. 65-66
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
- Claes, Julien, et al.
(författare)
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Nitric oxide in the control of luminescence from lantern shark (Etmopterus spinax)
- 2010
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Ingår i: JOURNAL OF EXPERIMENTAL BIOLOGY. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 213:17, s. 3005-3011
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Photophores (photogenic organs) of the lantern shark Etmopterus spinax are under hormonal control, with prolactin (PRL) and melatonin (MT) triggering the light emission. Differential sensitivity to these hormones in adult individuals suggests, however, that the luminescence of this shark is controlled by an additional mechanism. In this study, different techniques were used to investigate a potential modulator of E. spinax luminescence-nitric oxide (NO). NO synthase (NOS)-like immunoreactivity (IR) was found in the photocytes (photogenic cells) of the photophores. In addition, acetylated tubulin IR also supported the presence of nerves running through the photogenic tissue and innervating different structural elements of the photophores: photocytes, pigmented cells from the iris-like structure and lens cells. Pharmacological experiments confirmed a modulatory action of NO on the hormonally induced luminescence: NO donors sodium nitroprusside (SNP) and hydroxylamine decreased the time to reach the maximum amplitude (TLmax) of MT-induced luminescence while these substances decreased the maximum amplitude of PRL-induced luminescence (and also the TLmax in the case of SNP). The small impact of the NOS inhibitor L-NAME on hormonally induced luminescence suggests that NO is only produced on demand. The cGMP analogue 8BrcGMP mimicked the effects of NO donors suggesting that the effects of NO are mediated by cGMP.
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| 6. |
- Duchatelet, L., et al.
(författare)
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Catecholamine Involvement in the Bioluminescence Control of Two Species of Anthozoans
- 2023
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Ingår i: Life. - 2075-1729. ; 13:9
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Tidskriftsartikel (refereegranskat)abstract
- Bioluminescence, the ability of living organisms to emit visible light, is an important ecological feature for many marine species. To fulfil the ecological role (defence, offence, or communication), bioluminescence needs to be finely controlled. While many benthic anthozoans are luminous, the physiological control of light emission has only been investigated in the sea pansy, Renilla koellikeri. Through pharmacological investigations, a nervous catecholaminergic bioluminescence control was demonstrated for the common sea pen, Pennatula phosphorea, and the tall sea pen, Funiculina quadrangularis. Results highlight the involvement of adrenaline as the main neuroeffector triggering clusters of luminescent flashes. While noradrenaline and octopamine elicit flashes in P. phosphorea, these two biogenic amines do not trigger significant light production in F. quadrangularis. All these neurotransmitters act on both the endodermal photocytes located at the base and crown of autozooids and specific chambers of water-pumping siphonozooids. Combined with previous data on R. koellikeri, our results suggest that a catecholaminergic control mechanisms of bioluminescence may be conserved in Anthozoans.
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| 7. |
- Dupont, Samuel, 1971, et al.
(författare)
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Abnormal forms in the brittle-star Amphipholis squamata: a field study
- 2002
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Ingår i: Journal of the Marine Biological Association of the United Kingdom. - 0025-3154. ; 82:3, s. 491-493
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Tidskriftsartikel (refereegranskat)abstract
- Deviation from pentamerism is a rare phenomenon in 5-armed echinoderm species. Qualitative and quantitative data front field observations of 14 populations around the world were used for a biogeographical study of this phenomenon, Four abnormal forms presenting deviation from the classical pentamerism of echinoderms were observed within the brittle-star species Amphipholis squamata. (Echinodermata: Ophiuroidea). Although these forms were rare in global populations (0.29%), they call reach important frequencies in some locations. Our results suggest that habitat structure has all influence oil the occurence of abnormal forms. Moreover, deviations from pentamerism are not a heritable character but are a consequence of environmental perturbations oil the metamorphosis of larvae and/or abnormal regeneration of arms.
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| 8. |
- Dupont, Samuel, 1971, et al.
(författare)
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Effect of beta-adrenergic antagonists on bioluminescence control in three species of brittlestars (Echinodermata: Ophiuroidea)
- 2004
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Ingår i: Comp Biochem Physiol C Toxicol Pharmacol. - 1532-0456. ; 138:1, s. 59-66
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Tidskriftsartikel (refereegranskat)abstract
- The role of adrenaline in the nervous control of bioluminescence in three brittlestar species, Amphiura filiformis, Amphipholis squamata, and Ophiopsila aranea, was assessed by testing two different beta-adrenergic antagonists (propranolol and labetalol) over a wide concentration range (10(-10)-10(-3)M). We compared the effects of analogues (active vs. inactive) of the same substance (L- and D-enantiomers of propranolol). Propranolol presented both specific and nonspecific effects: (i) nonspecific effects were observed at the higher concentrations tested (10(-4) and 10(-3)M) in all three species; (ii) specific effects were detected only at the lower concentrations tested (10(-6)-10(-5)M). In A. squamata, the involvement of adrenaline in the nervous control of luminescence is supported by propranolol and labetolol specific inhibition. The neuropharmacological implications of nonspecific effects, the involvement of adrenaline and the interspecific differences in the brittlestar nervous control of bioluminescence are discussed.
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| 9. |
- Gouveneaux, A., et al.
(författare)
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Morphology and fluorescence of the parapodial light glands in Tomopteris helgolandica and allies (Phyllodocida: Tomopteridae)
- 2017
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Ingår i: Zoologischer Anzeiger. - : Elsevier BV. - 0044-5231. ; 268, s. 112-125
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Tidskriftsartikel (refereegranskat)abstract
- The histology of putative light organs in the parapodia of five species of Tomopteris (pelagic annelids) is examined and compared using light, epifluorescence and scanning electron microscopy. The structural homology of rosette glands in the parapodial pinnae of the tail-bearing species T. helgolandica and T. pacifica, and hyaline glands of the tail-less species T. carpenteri, T. planktonis and T. septentrionalis is highlighted. However, the rosette glands point towards the ramus of the coelomic cavity inside the parapodia, whereas the hyaline glands point towards the surrounding water and penetrate the pinnal surface on the posterior side of the parapodia. Further, in order to assess the photogenic properties of rosette glands from T. helgolandica, we analysed the distribution and the temporal dynamics of their endogenous fluorescence in isolated parapodia in response to light emission induced by I
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| 10. |
- Krönström, Jenny, 1978, et al.
(författare)
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Nitric oxide in control of luminescence from hatchetfish (Argyropelecus hemigymnus) photophores
- 2005
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 208:15, s. 2951-2961
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Tidskriftsartikel (refereegranskat)abstract
- Nitric oxide synthase-like immunoreactivity (NOS-LI IR) was detected by immunohistochemistry in ventral light organs of the mesopelagic fish, Argyropelecus hemigymnus. Strong NOS-LI IR was present in nerve fibres and in other cells central for production or modulation of light: immunoreactive fibres surrounded the photophores, and were also present in the filter area. Filter cells, particularly in the outer layers, showed strong IR throughout the cytoplasm. Pharmacological studies suggested that nitric oxide (NO) modulates adrenaline-stimulated light emission, and that the modulation is correlated to the ability of the light organ to respond to adrenaline. Adrenaline is known to produce two different types of light response in isolated photophores from Argyropelecus: a slow, long-lasting, high intensity response, or a fast and weak response of short duration. Incubation of photophores in the NO donors sodium nitroprusside or S-nitroso-N-acetylpenicillamine prior to adrenaline stimulation reduced the intensity of the strong and long-lasting type of response, but had little or even a potentiating effect on the weakly responding photophores. Hydroxylamine, which is converted to NO if catalase activity is present in the tissue, reduced the duration and the intensity of the adrenaline response in all tested organs. The NOS-inhibitor L-thiocitrulline potentiated the adrenaline response in the weakly responding organs; the weaker the adrenaline effect, the stronger the potentiation caused by L-thiocitrulline. The strongly responding organs were instead inhibited by L-thiocitrulline. The results suggest that NO has an important role in the control of light emission from Argyropelecus hemigymnus photophores. The cGMP analogue dibutyryl cGMP, the guanylate cyclase inhibitor ODQ and the phosphodiesterase inhibitor pentoxiphylline had no effect, indicating that the NO effect does not involve cGMP.
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