Purification par chromatographie liquide de haute pression (HPLC) de l'hormone cérébrale chez Nereis diversicolor et Perinereis cultrifera (Annélides Polychètes)
Abstract:Summary. Purification of the brain hormone of Nereis diversicolor and Perinereis cultrifera (Annelida : Polychaeta) by high-pressure liquid chromatography (HPLC).Five thousand brains inhibiting gametogenesis in Nereis diversicolor and Perinereis cultrifera were extracted with cold methanol, giving a micromolecular fraction containing the whole of the inhibitory activity of the brains. This micromolecular fraction, fractionated (i) on Sephadex G 25 fine and (ii) on Sephadex G 25 superfine, gave an inhibitory pe… Show more
“…In particular, germ cells were resorbed and the ability to regenerate lost segments was re-established (Golding and Yuwono, 1994). These findings highlight the exceptional importance of neuroendocrine signals in semelparous reproduction and suggest that the underlying molecular mechanisms are conserved across different annelids (Hauenschild, 1956b, 1959; Golding, 1967a, 1967b; Durchon and Porchet, 1970; Hofmann, 1976; Cardon et al, 1981; Golding, 1983; Golding and Yuwono, 1994). 10.7554/eLife.17126.003Figure 1. Vitellogenin expression in eleocytes is a quantitative measure for the maturation stage of Platynereis , allowing for the establishment of a bioassay to purify the enigmatic brain hormone, nereidin.( A ) Scheme summarising the critical role of the brain hormone nereidin in energy expenditure, as derived from classical experiments: Before maturation (left), high nereidin levels sustain somatic growth, but repress reproduction; drops in nereidin activity levels initiate the generation of germ cells and sexual maturation (right).…”
Section: Introductionmentioning
confidence: 76%
“…Fractionated head extracts could be shown to interfere with the transition of cultured spermatogonia to spermatozoa (Cardon, 1970; Durchon and Porchet, 1970; Cardon et al, 1981). However, the respective assay required more than a week of culturing and substantial input material (thousands of sampled heads).…”
Section: Resultsmentioning
confidence: 99%
“…However, the respective assay required more than a week of culturing and substantial input material (thousands of sampled heads). Using this qualitative assay, and systematic fractionating of head extracts, the brain hormone activity could be associated with a small (M R ≤ 2.000), lipophilic molecule (Cardon, 1970; Durchon and Porchet, 1970; Cardon et al, 1981). …”
Section: Resultsmentioning
confidence: 99%
“…Insight into the molecules regulating these extreme shifts of energy expenditure has remained limited (Cardon et al, 1981; Mommsen, 2004; Hébert Chatelain et al, 2008). This can largely be attributed to the lack of an appropriate laboratory model system amenable to molecular research.…”
Section: Introductionmentioning
confidence: 99%
“…Based on this hypothesis, large-scale purifications have been performed from head extracts of N. diversicolor and Perinereis cultrifera (Cardon et al, 1981). These finally resulted in the identification of a hexapeptide (PPGPPG).…”
Animals require molecular signals to determine when to divert resources from somatic functions to reproduction. This decision is vital in animals that reproduce in an all-or-nothing mode, such as bristle worms: females committed to reproduction spend roughly half their body mass for yolk and egg production; following mass spawning, the parents die. An enigmatic brain hormone activity suppresses reproduction. We now identify this hormone as the sesquiterpenoid methylfarnesoate. Methylfarnesoate suppresses transcript levels of the yolk precursor Vitellogenin both in cell culture and in vivo, directly inhibiting a central energy–costly step of reproductive maturation. We reveal that contrary to common assumptions, sesquiterpenoids are ancient animal hormones present in marine and terrestrial lophotrochozoans. In turn, insecticides targeting this pathway suppress vitellogenesis in cultured worm cells. These findings challenge current views of animal hormone evolution, and indicate that non-target species and marine ecosystems are susceptible to commonly used insect larvicides.DOI:
http://dx.doi.org/10.7554/eLife.17126.001
“…In particular, germ cells were resorbed and the ability to regenerate lost segments was re-established (Golding and Yuwono, 1994). These findings highlight the exceptional importance of neuroendocrine signals in semelparous reproduction and suggest that the underlying molecular mechanisms are conserved across different annelids (Hauenschild, 1956b, 1959; Golding, 1967a, 1967b; Durchon and Porchet, 1970; Hofmann, 1976; Cardon et al, 1981; Golding, 1983; Golding and Yuwono, 1994). 10.7554/eLife.17126.003Figure 1. Vitellogenin expression in eleocytes is a quantitative measure for the maturation stage of Platynereis , allowing for the establishment of a bioassay to purify the enigmatic brain hormone, nereidin.( A ) Scheme summarising the critical role of the brain hormone nereidin in energy expenditure, as derived from classical experiments: Before maturation (left), high nereidin levels sustain somatic growth, but repress reproduction; drops in nereidin activity levels initiate the generation of germ cells and sexual maturation (right).…”
Section: Introductionmentioning
confidence: 76%
“…Fractionated head extracts could be shown to interfere with the transition of cultured spermatogonia to spermatozoa (Cardon, 1970; Durchon and Porchet, 1970; Cardon et al, 1981). However, the respective assay required more than a week of culturing and substantial input material (thousands of sampled heads).…”
Section: Resultsmentioning
confidence: 99%
“…However, the respective assay required more than a week of culturing and substantial input material (thousands of sampled heads). Using this qualitative assay, and systematic fractionating of head extracts, the brain hormone activity could be associated with a small (M R ≤ 2.000), lipophilic molecule (Cardon, 1970; Durchon and Porchet, 1970; Cardon et al, 1981). …”
Section: Resultsmentioning
confidence: 99%
“…Insight into the molecules regulating these extreme shifts of energy expenditure has remained limited (Cardon et al, 1981; Mommsen, 2004; Hébert Chatelain et al, 2008). This can largely be attributed to the lack of an appropriate laboratory model system amenable to molecular research.…”
Section: Introductionmentioning
confidence: 99%
“…Based on this hypothesis, large-scale purifications have been performed from head extracts of N. diversicolor and Perinereis cultrifera (Cardon et al, 1981). These finally resulted in the identification of a hexapeptide (PPGPPG).…”
Animals require molecular signals to determine when to divert resources from somatic functions to reproduction. This decision is vital in animals that reproduce in an all-or-nothing mode, such as bristle worms: females committed to reproduction spend roughly half their body mass for yolk and egg production; following mass spawning, the parents die. An enigmatic brain hormone activity suppresses reproduction. We now identify this hormone as the sesquiterpenoid methylfarnesoate. Methylfarnesoate suppresses transcript levels of the yolk precursor Vitellogenin both in cell culture and in vivo, directly inhibiting a central energy–costly step of reproductive maturation. We reveal that contrary to common assumptions, sesquiterpenoids are ancient animal hormones present in marine and terrestrial lophotrochozoans. In turn, insecticides targeting this pathway suppress vitellogenesis in cultured worm cells. These findings challenge current views of animal hormone evolution, and indicate that non-target species and marine ecosystems are susceptible to commonly used insect larvicides.DOI:
http://dx.doi.org/10.7554/eLife.17126.001
The sections in this article are:
Growth and Morphogenetic Factors
Insects
Crustaceans
Molluscs
Other Invertebrates
Regenerative Factors
Crustaceans
Insects
Cnidarians
Platyhelminths
Annelids
Echinoderms
Others
Pigmentary Factors
Crustaceans
Insects
Osmoregulatory Factors
Factors that May Increase Osmotic Pressure
Factors that May Decrease Osmotic Pressure
Metabolic Factors
Biogenic Amines
JHs
and Farnesylacetone
Adipokinetic Hormones and
RPCH
Crustacean Hyperglycemic Hormones
Other Metabolic Factors
Reproductive Factors
Flatworms, Nemertines, and Nematodes
Molluscs
Crustaceans
Insects
Other Arthropods
Annelids
Echinoderms
Behavioral Factors
In Vitro Studies
In Vivo Studies
Pheromones
Summary
Regeneration is the process by which many animals are able to restore lost or injured body parts. After amputation of the posterior part of its body, the annelid Platynereis dumerilii is able to regenerate the pygidium, the posteriormost part of its body that bears the anus, and a subterminal growth zone containing stem cells that allows the subsequent addition of new segments. The ability to regenerate their posterior part (posterior regeneration) is promoted, in juvenile worms, by a hormone produced by the brain and is lost when this hormonal activity becomes low at the time the worms undergo their sexual maturation. By characterizing posterior regeneration at the morphological and molecular levels in worms that have been decapitated, we show that the presence of the head is essential for multiple aspects of posterior regeneration, as well as for the subsequent production of new segments. We also show that methylfarnesoate, the molecule proposed to be the brain hormone, can partially rescue the posterior regeneration defects observed in decapitated worms. Our results are therefore consistent with a key role of brain hormonal activity in the control of regeneration and growth in P. dumerilii, and support the hypothesis of the involvement of methylfarnesoate in this control.
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