21 research outputs found

    Characterization of Terpenoids from the Root of Ceriops tagal with Antifouling Activity

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    One new dimeric diterpenoid, 8(14)-enyl-pimar-2′(3′)-en-4′(18′)-en-15′(16′)-endolabr- 16,15,2′,3′-oxoan-16-one (1) and five known terpenoids: Tagalsin C (2), Tagalsin I (3), lup-20(29)-ene-3β,28-diol (4), 3-oxolup-20(29)-en-28-oic acid (5) and 28-hydroxylup- 20(29)-en-3-one (6) were isolated from the roots of the mangrove plant Ceriops tagal. Their structures and relative stereochemistry were elucidated by means of extensive NMR, IR and MS analysis. The antifouling activity against larval settlement of the barnacle Balanus albicostatus were evaluated using capsaicin as a positive control. All these terpenoids exhibited antifouling activity against cyprid larvae of the barnacle without significant toxicity. The structure-activity relationship results demonstrated that the order of antifouling activity was diterpenoid (Compound 2) > triterpenoid (Compounds 4, 5 and 6) > dimeric diterpenoid (Compounds 1 and 3). The functional groups on the C-28 position of lupane triterpenoid significantly affect the antifouling activity. The diterpenoid dimmer with two identical diterpenoid subunits might display more potent antifouling activity than one with two different diterpenoid subunits. The stability test showed that Compounds 2, 4, 5 and 6 remained stable over 2-month exposure under filtered seawater

    Autonomy of the Major Claw Stimulates Molting and Supresses Feeding in Fiddler Crabs

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    Autotomy is a predator escape mechanism in many taxa, including crustaceans. Male fiddler crabs autotomize the major claw, despite its importance in mating, territoriality, and thermoregulation. This claw can be regenerated through molting. We investigated major claw autotomy in the fiddler crab Leptuca pugilator, testing hypotheses that (1) autotomy of the major claw accelerates the molting process, reflecting the importance of this appendage, (2) autotomy of the major claw results in increased feeding to accumulate energy reserves needed for regeneration, (3) this change in feeding is hormonally driven. Autotomy of the major claw accelerated molting. Yet contrary to expectations, autotomy of the claw initially inhibited feeding, with evidence for release of feeding inhibitory factor. These effects are specific to the major claw, and were not seen following autotomy of a walking leg. Acceleration of molting following autotomy of the major claw appears to be an adaptive response reflecting the costs of being without this multi-function structure

    MAGNESIUM DEPENDENCE OF ENDOTOXIN-INDUCED DEGRANULATION OF LIMULUS AMEBOCYTES

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    Volume: 171Start Page: 330End Page: 33

    CHEMOTAXIS OF OYSTER DRILLS UROSALPINX CINEREA TO COMPETING PREY ODORS

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    Volume: 164Start Page: 536End Page: 54

    CHEMICAL ATTRACTION OF NEWLY HATCHED OYSTER DRILLS

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    Volume: 164Start Page: 493End Page: 50
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