Fine structure of the cerebral and pygidial ocelli in Chone ecaudata (polychaeta: sabellidae)

Ermak, Thomas H.; Eakin, Richard M.

doi:10.1016/s0022-5320(76)80154-2

Cited by 124 publications

(59 citation statements)

References 23 publications

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“…For transmission electron microscopy specimens were then prefixed in a phosphate-buffered mixture of sucrose, picric acid, glutaraldehyde and paraformaldehyde (SPAFG; Ermak and Eakin, 1976) for 2.5 h at 48C. After rinsing in the same buffer they were postfixed in buffered 1% OsO 4 for 1 h at 48C, dehydrated through a graded ethanol series (from 30 to 100%), transferred to propylene oxide, and infiltrated by the embedding medium overnight in a 1:3 mixture of embedding medium and propylene oxide.…”

Section: Methodsmentioning

confidence: 99%

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Wilkens

Purschke

2009

Journal of Morphology

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The phylogenetic position of Orbiniidae within Annelida is unresolved. Conflicting hypotheses place them either in a basal taxon Scolecida, close to Spionida, or in a basal position in Aciculata. Because Aciculata have a specific type of eye, the photoreceptive organs in the orbiniid Scoloplos armiger were investigated to test these phylogenetic hypotheses. Two different types of prostomial photoreceptor-like sense organs were found in juveniles and one additional in subadults. In juveniles there are four ciliary photoreceptor-like phaosomes with unbranched cilia and two pigmented eyes. The paired pigmented eyes lie beside the brain above the circumoesophageal connectives. Each consists of one pigmented cell, one unpigmented supportive cell and three everse rhabdomeric sensory cells with vestigial cilia. During development the number of phaosomes increases considerably and numerous unpigmented sense organs appear consisting of one rhabdomeric photoreceptor cell and one supportive cell. The development and morphology of the pigmented eyes of S. armiger suggest that they represent miniaturized eyes of the phyllodocidan type of adult eye rather than persisting larval eyes resulting in small inverse eyes typical of Scolecida. Moreover, the structure of the brain indicates a loss of the palps. Hence, a closer relationship of Orbiniidae to Phyllodocida is indicated. Due to a still extensive lack of ultrastructural data among polychaetes this conclusion cannot be corroborated by considering the structure of the unpigmented ciliary and rhabdomeric photoreceptor-like sense organs.

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Section: Methodsmentioning

confidence: 99%

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Wilkens

Purschke

2009

Journal of Morphology

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“…For electron microscopy, specimens were fixed in a phosphatebuffered mixture of sucrose, picric acid, glutaraldehyde and paraformaldehyde (SPAFG) (Ermak and Eakin, 1976) for 2.5 h at 4°C and rinsed in phosphate buffer adjusted to the osmolarity of seawater (4°C, pH 7.2, 12% sucrose). Post-fixation occurred in 1% OsO 4 for 1 h ( phosphate buffered as above) and dehydrated in a graded ethanol series.…”

Section: Electron Microscopymentioning

confidence: 99%

Ammonia excretion in the marine polychaeteEurythoe complanata(Annelida)

Thiel

Hugenschütt

Meyer

et al. 2016

Journal of Experimental Biology

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Ammonia is a toxic waste product from protein metabolism and needs to be either converted into less toxic molecules or, in the case of fish and aquatic invertebrates, excreted directly as is. In contrast to fish, very little is known regarding the ammonia excretion mechanism and the participating excretory organs in marine invertebrates. In the current study, ammonia excretion in the marine burrowing polychaete Eurythoe complanata was investigated. As a potential site for excretion, the 100-200 µm long, 30-50 µm wide and up to 25 µm thick dentrically branched, well ventilated and vascularized branchiae (gills) were identified. In comparison to the main body, the branchiae showed considerably higher mRNA expression levels of Na + /K + -ATPase, V-type H + -ATPase, cytoplasmic carbonic anhydrase (CA-2), a Rhesus-like protein, and three different ammonia transporters (AMTs). Experiments on the intact organism revealed that ammonia excretion did not occur via apical ammonia trapping, but was regulated by a basolateral localized V-type H + -ATPase, carbonic anhydrase and intracellular cAMP levels. Interestingly, the V-type H + -ATPase seems to play a role in ammonia retention. A 1 week exposure to 1 mmol l −1 NH 4 Cl (HEA) did not cause a change in ammonia excretion rates, while the three branchial expressed AMTs showed a tendency to be down-regulated. This indicates a shift of function in the branchial ammonia excretion processes under these conditions.

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“…Westheide 1967 (from intertidal areas of the Island of Sylt, North Sea) and Trilobodrilus heideri Remane, 1925 (from subtidal sediments off the Island of Helgoland, North Sea; for data of the collecting site see yon Nordheim, 1984) were investigated with TEM techniques. After relaxation in a MgC12-solution the animals were fixed at 4 °C in SPAFG (sucrose-picric-acid-formaldehyde-glutaraldehyde) in phosphate buffer (+10 % sucrose) for lh (Ermak & Eakin, 1976). Then the specimens were rinsed in phosphate buffer (+10 % sucrose; pH 7.3) for 2h, postfixed at 4 °C in phosphate-buffered osmium tetroxide for lh, dehydrated in an ethanol series, embedded in an Epon-Araldite mixture, and sectioned with a diamond knife on a Reichert Uttracut, The sections were stained with aqueous uranyl acetate and lead citratel the photographs were taken with a Zeiss EM 10,…”

Section: Introductionmentioning

confidence: 99%

Ultrastructure of sperm morphology ofTrilobodrilus axi andT. heideri (Dinophilidae, Polychaeta)

Scharnofske

1986

Helgolander Meeresunters

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The ultrastructure of the sperm of the dinophilids Trilobodrilus ax/and Trilobodrilus heideri was investigated. The sperms are extremely modified and show an elongated head, middle piece, and tail region, which are overlapping. This condition is a synapomorphous feature for the dinophilids. The sperm structure has to be related to the specialized mode of sperm transfer by hypodermal injection in these species.

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Fine structure of the cerebral and pygidial ocelli in Chone ecaudata (polychaeta: sabellidae)

Cited by 124 publications

References 23 publications

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Pigmented eyes, photoreceptor‐like sense organs and central nervous system in the polychaete Scoloplos armiger (Orbiniidae, Annelida) and their phylogenetic importance

Ammonia excretion in the marine polychaeteEurythoe complanata(Annelida)

Ultrastructure of sperm morphology ofTrilobodrilus axi andT. heideri (Dinophilidae, Polychaeta)

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