Platynereis dumerilii

Source: Wikipedia, the free encyclopedia.

Platynereis dumerilii
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Annelida
Clade: Pleistoannelida
Subclass: Errantia
Order: Phyllodocida
Family: Nereididae
Genus: Platynereis
Species:
P. dumerilii
Binomial name
Platynereis dumerilii
(
Audouin & Milne-Edwards, 1834[1]
)
Synonyms
List
  • Eunereis africana Treadwell, 1943
  • Heteronereis fucicola Örsted, 1843
  • Heteronereis maculata Bobretzky, 1868
  • Heteronereis malmgreni Claparède, 1868
  • Iphinereis fucicola (Örsted, 1843)
  • Leontis dumerilii (Audouin & Milne Edwards, 1833)
  • Leptonereis maculata Treadwell, 1928
  • Mastigonereis quadridentata Schmarda, 1861
  • Mastigonereis striata Schmarda, 1861
  • Nereilepas variabilis Örsted, 1843
  • Nereis (Platynereis) dumerilii Audouin & Milne Edwards, 1833
  • Nereis (Platynereis) dumerilii striata (Schmarda, 1861)
  • Nereis (Platynereis) striata (Schmarda, 1861)
  • Nereis agilis Keferstein, 1862
  • Nereis alacris Verrill, 1880
  • Nereis antillensis McIntosh, 1885
  • Nereis dumerilii Audouin & Milne Edwards, 1833
  • Nereis glasiovi Hansen, 1882
  • Nereis gracilis Hansen, 1882
  • Nereis megodon Quatrefages, 1866
  • Nereis peritonealis Claparède, 1868
  • Nereis taurica Grube, 1850
  • Nereis zostericola Örsted, 1843
  • Platynereis dumerili [lapsis]
  • Platynereis jucunda Kinberg, 1865
  • Platynereis striata (Schmarda, 1861)
  • Uncinereis lutea Treadwell, 1928
  • Uncinereis trimaculosa Treadwell, 1940
Female epitoke of Platynereis dumerilii: Its body is filled with yellow eggs.[2]
Male epitoke of Platynereis dumerilii: Its frontal part is filled with white sperm, while its rear is red due to blood vessels.[2]

Platynereis dumerilii is a species of

Pacific, and the Kerguelen Islands.[4] Platynereis dumerilii is today an important lab animal,[5] it is considered as a living fossil,[6][7][8] and it is used in many phylogenetic
studies as a model organism.

Description

Platynereis dumerilii is a small marine ragworm: Males reach a length of 2 to 3 cm, while females reach a length of 3 to 4 cm.[9] Like a number of invertebrate phyla, Platynereis dumerilii has an axochord, a paired longitudinal muscle that displays striking similarities to the notochord regarding position, developmental origin, and expression profile.[10] Its early trochophore larva has a pair of the simplest eyes in the animal kingdom, each eye consists only of a photoreceptor cell and a pigment cell.[11]

Locomotion

P. dumerilii worms have a ciliated surface which beats synchronously to drive locomotion and fluid flow. Larvae have segmental multiciliated cells that regularly display spontaneous coordinated ciliary arrests, which compose the ciliomotor circuitry in the worms. Whole-body coordination of ciliary locomotion is performed by a "stop-and-go pacemaker system".[12]

As the worms develop, they use chaetae, and then parapodia, for locomotion. Unlike other polychaetes, in Platynereis larvae, the parapodia are used only for navigation while the cilia are responsible for propulsive force.[2]

Senses

Photoreceptor cells

Platynereis dumerilii larvae possess two kinds of

Rhabdomeric and ciliary
photoreceptor cells.

The ciliary photoreceptor cells are located in the deep brain of the larva. They are not shaded by

UV-sensitive (λmax = 383 nm),[14] and the ciliary photoreceptor cells react on non-directional UV-light by making the larvae swimming down. This forms a ratio-chromatic depth-gauge with phototaxis of the rhabdomeric photoreceptor cells of the eyes.[15]

A rhabdomeric photoreceptor cell forms with a pigment cell a simple eye.

nectochaete larva, phototaxis is mediated by the more complex adult eyes.[17] The adult eyes express at least three opsins: Two rhabdomeric opsins and a Go-opsin.[18][19] The three opsins there mediate phototaxis all the same way via depolarization,[19] even so a scallop Go-opsin is known to hyperpolarize.[20][21]

Chemical

P. dumerilii senses chemicals with four types of organs: The antennae, the palps, the nuchal organs, and the tentacular cirri. These organs detect food and chemical cues such as alcohols, esters, amino acids, and sugars.[22]

Among the four types, the antennae are the primary chemosensory organs and sense a broad range of chemicals, while the palps are specialized on taste, which means they detect food-related chemicals. The cirri are thin thread-like head appendages and are specialized in tactile sensation, but can also give spatial information from were a chemical cue is coming, since a single stimulus can elicit in the left and right cirrus a response at a different times.[22] The cirri also sense light: When they are shaded, the worm retreats rapidly into its tube to protect them. This behavior is called a shadow reflex.[23] The nuchal organ is a singular ciliated pit in P. dumerilii. Among annelids, nuchal organs are conserved and seem to have an important chemosensory function. However, what their exact function is, is still unclear.[22]

The signals from the four chemosensory organs are processed in a lateral region and in the

mushroom bodies.[22] The mushroom bodies in annelids resemble those in insects by anatomy, morphology and gene expression. So probably, annelids and insects inherited mushroom bodies from their last common ancestor.[24]

Habitat

Platynereis dumerilii builds tubes on its

thermal vents[35][36] or polluted areas near sewer outfall pipes.[37] It dominates polluted areas[38][39] and acidic areas with pH values around 6.5[40] fitting the preferred pH value of a subpopulation of late Platynereis dumerilii nectochaete larvae.[41] Larvae feed on plankton, and migrate vertically in the ocean in response to changes in light, causing a daily transport of biomass.[42]

Reproduction and development

Platynereis dumerilii is

Bay of Naples, where it displays reproductive synchrony. The adult worms rise en masse to the water surface a few days after the full moon, during a one- to two-hour dark portion of the night between sunset and moonrise. In the worm’s natural environment, it is important to synchronize spawning to increase the potential for gametes to meet and fertilize. By detecting nighttime lighting in accordance with the lunar cycle, the worms synchronize reproductive activity. Worms that make L-Cry protein are better able to detect appropriate light conditions and synchronize the release of gametes. In addition, the molecule r-Opsin is extremely sensitive to light, and appears to help detect moonrise. Some combination of signals from r-Opsin and L-Cry is believed to help the worms to coordinate rising at a common time to spawn.[44][45][46]

During mating, the male swims around the female while the female is swimming in small circles. Both release eggs and sperm into the water. This release is triggered by sexual pheromones. The eggs are then fertilized outside of the body in the water.[47] Like other Nereidids, Platynereis dumerilii has no segmental gonades, the oocytes mature freely swimming in the body cavity (coelom),[43] and stain the body of the mature female epitoke yellow.[2]

Platynereis dumerilii develops very stereotypically between batches and therefore time can be used to stage Platynereis dumerilii larvae. However, the temperature influences the speed of development greatly.[2] Therefore, the following developmental times are given with 18 °C as reference temperature:

After 24 hours, a fertilized egg gives rise to a

parapodia bearing chaetae, which serve for locomotion.[2] The nectochaete larva can switch from positive to negative phototaxis.[17] After five to seven days, the larvae start feeding and develop on their own speed, depending on food supply. After three to four weeks, when six segments have formed, the head is formed.[2]

Normal development is subdivided into 16 stages.[2] Platynereis dumerilii lives for 3 up to 18 months[5] with an average lifespan of seven months. P. dumerilii reproduces only once,[42] and dies after delivering its gametes.[2]

Genome

The genome of Platynereis dumerilii is diploid (2n chromosomes) with a haploid set of n = 14 chromosomes.[9][48] It contains approximately 1 Gbp (giga base pairs) or 109 base pairs.[49] This genome size is close to the average observed for other animals. However, compared to many classical invertebrate molecular model organisms, this genome size is rather large and therefore it is a challenge to identify gene regulatory elements that can be far away from the corresponding promoter. But it is intron rich unlike those of Drosophila melanogaster and Caenorhabditis elegans and thus closer to vertebrate genomes including the human genome.[50]

Bristle worms contain the complex protein

crustaceans (e.g. daphnia). It was once believed that haemoglobin must have evolved multiple times to be a feature of such different species.Comparing bristle worms with other red blooded species suggests that all forms of haemoglobins are derived from a single ancestral gene, cytoglobin.[51][52]

References

  1. ^
    doi:10.5962/bhl.title.43796
    .
  2. ^
    PMID 21192805
    .
  3. ^ Read, G. "Platynereis dumerilii (Audouin & Milne Edwards, 1834). In: Read, G.; Fauchald, K. (Ed.) (2015)". World Register of Marine Species. Retrieved 26 November 2015.
  4. ^ a b Fauvel, Pierre (1914). "Annélides polychètes non-pélagiques provenant des campagnes de l'Hirondelle et de la Princesse-Alice (1885-1910)". Résultats des Campagnes Scientifiques Accompliés Par le Prince Albert I. 46: 1–432.
  5. ^
    PMID 14988933
    .
  6. ^ "Introduction - Encyclopedia of Life". Encyclopedia of Life. Retrieved 14 July 2017.
  7. ^ "Living Fossil Platynereis dumerilii: Unraveling the first steps of eye evolution". thebiologyplace. 3 December 2008. Retrieved 14 July 2017.
  8. ^ "Arendt Group - Evolution of the nervous system in bilateria - EMBL". www.embl.de. Retrieved 14 July 2017.
  9. ^
    S2CID 84763134
    .
  10. S2CID 20045151
    .
  11. ^
    PMID 19020621
    .
  12. PMID 28508746
    .
  13. S2CID 2583520
    .
  14. PMID 28623234
    .
  15. PMID 29809157
    .
  16. ^
    S2CID 46930876
    .
  17. ^
    PMID 24867217
    .
  18. ^
    PMID 23667045
    .
  19. ^
    PMID 26255845
    .
  20. PMID 9287291
    .
  21. PMID 10884309
    .
  22. ^
    PMID 30381362
    .
  23. PMID 29669554
    .
  24. S2CID 258754.{{cite journal}}: CS1 maint: date and year (link
    )
  25. ^
    doi:10.1016/0022-0981(88)90006-8
    .
  26. ^ a b Lewis, III, F. Graham; Stoner, Allan W. (1 January 1981). "An Examination of Methods for Sampling Macrobenthos in Seagrass Meadows". Bulletin of Marine Science. 31 (1): 116–124.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  27. doi:10.1016/0304-3770(79)90079-2
    .
  28. PMID 25414525
    .
  29. S2CID 84660433
    .
  30. S2CID 250949017
    .
  31. ^
    S2CID 85293536
    .
  32. doi:10.1111/j.1439-0485.1992.tb00337.x
    .
  33. doi:10.3989/scimar.1999.63n2137
    .
  34. S2CID 53159295
    .
  35. ^ Giménez, F.; Marín, A. (1991). "Los Anelidos poliquetos de una solfatara submarina en el Golfo de Napoles". Anales de Biología. 17: 143–151.
  36. PMID 26156262
    .
  37. ^ Surugiu, Victor; Feunteun, Marc (2008). "The structure and distribution of polychaete populations influenced by sewage from the Romanian Coast of the Black Sea". Analele Ştiinţifice Ale Universităţii "Al. I. Cuza" Iaşi, S. Biologie Animală. LIV.
  38. doi:10.1016/0025-326x(80)90048-X
    .
  39. doi:10.3354/meps07989
    .
  40. S2CID 84767827
    .
  41. PMID 26517120
    .
  42. ^ a b "A slightly different worm – Platynereis dumerilii". www.gesundheitsindustrie-bw.de. Retrieved 2019-12-08.
  43. ^
    S2CID 38397888
    .
  44. doi:10.1146/knowable-022223-2
    . Retrieved 6 March 2023.
  45. ISSN 1941-1405
    .
  46. PMID 36064778
    .
  47. S2CID 42318049
    .
  48. ^ Ipucha, María Claudia; Santos, Cinthya Gomes; Lana, Paulo Da Cunha; Sbalqueiro, Ives José (2007). "Cytogenetic characterization of seven South American species of nereididae (annelida: polychaeta): implications for the karyotypic evolution". BAG. Journal of Basic and Applied Genetics. 18 (2).
  49. PMID 24807110
    .
  50. S2CID 23653039
    .
  51. ^ "A single gene 'invented' haemoglobin several times". EurekAlert!. 29 December 2020. Retrieved 13 March 2023.
  52. PMID 33371890
    .

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