Dormancy among the Porifera: Gemmule Formation and Germination in Fresh-Water and Marine Sponges

Simpson, Tracy L.; Fell, Paul E.

doi:10.2307/3225157

Cited by 85 publications

(57 citation statements)

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“…Conserved domains were identified with the hmmscan program from the HMMER 3.0 package against the SMART database (version of August 2012). (54), and we found that it was also incorporated into the abundant vitelline platelets present in the archeocyte cytoplasm (probably because the vitelline platelets contain mitochondria) (55 . The cell collection device was maintained at 4°C throughout the procedure.…”

Section: Methodsmentioning

confidence: 70%

The ancestral gene repertoire of animal stem cells

Alié

Hayashi²,

Sugimura

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

113

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Stem cells are pivotal for development and tissue homeostasis of multicellular animals, and the quest for a gene toolkit associated with the emergence of stem cells in a common ancestor of all metazoans remains a major challenge for evolutionary biology. We reconstructed the conserved gene repertoire of animal stem cells by transcriptomic profiling of totipotent archeocytes in the demosponge Ephydatia fluviatilis and by tracing shared molecular signatures with flatworm and Hydra stem cells. Phylostratigraphy analyses indicated that most of these stem-cell genes predate animal origin, with only few metazoan innovations, notably including several partners of the Piwi machinery known to promote genome stability. The ancestral stem-cell transcriptome is strikingly poor in transcription factors. Instead, it is rich in RNA regulatory actors, including components of the "germ-line multipotency program" and many RNA-binding proteins known as critical regulators of mammalian embryonic stem cells.Porifera | stem cells | evolution | uPriSCs | RNA binding

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Section: Methodsmentioning

confidence: 70%

The ancestral gene repertoire of animal stem cells

Alié

Hayashi²,

Sugimura

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

113

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“…Harper (1977) cites numerous strategies which have evolved in terrestrial plants to escape physical stress and predation. In the aquatic environment, freshwater green filamentous algae of the genus Oedogonium produce and release zoospores in response to rises in temperature or decreases in light intensity (Klebs, 1928;Erben, 1962) In the invertebrates, some sponges produce gemmules asexually with the onset of winter (Hyman, 1940;Simpson and Fell, 1974). Some freshwater ectoprocts (e.g.…”

Section: Field Observationsmentioning

confidence: 99%

Polyp Bail-Out: An Escape Response to Environmental Stress and a New Means of Reproduction in Corals

Sammarco¹

1982

Mar. Ecol. Prog. Ser.

151

107

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During a study of planulation in the central region of the Great Barrier Reef, it was determined that the coral Seriatopora hystrix Dana exhibits an escape response to environmental stress. Th.is response, which occurs relatively rapidly, has been termed 'polyp bail-out', It proceeded in 3 steps: (1) Isolation of individual polyps via the polyp-ward movement of coenosarc; (2) emergenceof polyps and detachment from the skeleton; (3) dispersal, re-attachment to the bottom, andsecretion o i a new skeleton. Of the 250 polyps observed 4 5 % successfully settled and secreted skeletons within 7 to 9 d under laboratory conditions. Polyps retained zooxantheIlae during the process and usually possessed 2 slightly adhesive filaments which may have assisted in re-attachment. Bail-out may be induced at any time in the laboratory and has been observed to occur naturally in the field on several occasions. The peak period of planulation for S. hystrix was determined to be November (early summer, southern hemisphere) During the normal spawning period, some polyps were observed to detach themselves while carrying active planulae. These polyps later disintegrated, releasing the larvae which settled normally. It is suggested that 'bail-out' may be one factor contributing to doininance of this species within certain reef habitats. It would also appear that this process of isolation and detachment of individuals from a coral followed by dispersal, re-settlement, and re-initiation of skeletenogenesis, represents a previously unknown mode of asexual reproduction in the Scleractinia.

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“…The vacuolization of some archeocytes observed in the present study (Figs 2b,3) are interpreted as stress related, not an indication of osmoregulation. Based on ionic comparisons of marine sponges and habitat water (PROSSER, 1967), the necessity of contractile vacuoles (at least under normal conditions) has been questioned because osmotic water loss rather than gain is to be expected (SIMPSON, 1984). However, several ecologic and experimental studies show that marine sponges readily invade brackish-water environments, particularly the euryhaline c1ionids ('oyster pests') that can live and function normally in 1.5-2.0 % salinity and can recovered from several days of exposure to salinities as low as 1.0 I~O (HOPKINS, 1956;HARTMAN, 1958).…”

Section: Histological Expression Of Stressmentioning

confidence: 99%

Low‐Tide Exposure of Sponges in a Caribbean Mangrove Community

Rützler

1995

Marine Ecology

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Abstract. Sponges on subtidal red-mangrovc prop roots may bccome exposed to air many times per year during very low tides. Full exposure is stressful and potentially fatal, particularly if occurring in full sun. Largc root sponges show distinct species zonation bctwcen mean low water and -0.5 m. Haliclol/a implex({ormis and Lis.I'oc!£'1ldoryx isodiclyali.l' arc ncar the top while Scopa!illo melderi arc ncar the lower end of thc rangc. Temporary experimental desiccation resulted in 100 % recovery of all three species after they had been exposed to either stln or shade for up to 2 h. Scopalina is the least rcsistant and lost over 90 1 }'o tissue within 3 days after the 4-h and 6-h experiments; the remaining cell mass succumbed to infestation by microbes. Haliclona and Lis.I'odelldoryx recovcred from as much as 6 h in full sun but lost 85% and 80% of the original tissue volume, respectively. In Lissotlelltloryx, clusters of larvae developed in the regcncrating fragmcnts. Watcr loss tolcrated by thc three species is estimated as 66 % of wet weight in Haliclolla. 54 % in Lissodelltloryx and 38 % in Sco{Jalilla. Salinity of interstitial seawater (porc water) extracted from exposcd spongcs rose from ambient 3.5 % to 4.3-4.8 % aftcr I h, to 5.1-5.9% aftcr 6 h. Most endobionts dicd or left their host during this last phase. Natural vertical zonation in thesc spongcs rcflects their resistance to tidal exposure.

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Dormancy among the Porifera: Gemmule Formation and Germination in Fresh-Water and Marine Sponges

Cited by 85 publications

References 0 publications

The ancestral gene repertoire of animal stem cells

The ancestral gene repertoire of animal stem cells

Polyp Bail-Out: An Escape Response to Environmental Stress and a New Means of Reproduction in Corals

Low‐Tide Exposure of Sponges in a Caribbean Mangrove Community

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