Tube worms

In the luminescence systems that require a peroxide or an active oxygen species in addition to molecular oxygen (the scaleworm, the tube worm Chaetopterus, the clam Pholas, the squid Symplecto-teuthis), their in vitro luminescence reactions reported are much slower and inefficient compared to their bright in vivo luminescence. The true, intrinsic activation factor in their in vivo luminescence should be determined, and the detailed mechanisms of oxidation should be elucidated. 

Although coral looks like a plant, actually it is mainly comprised of (10) the limestone skeleton of a tiny animal called a coral polyp. While corals are the main components of reef structure, they are not the only living participants. Coralline algae cement the myriad corals, and other miniature organisms such as tube worms and mollusks contribute skeletons to this dense and diverse structure. Together, these (15) living creatures construct many different types of tropical reefs. 

Many of the animals harbor endosymbiotic bacteria that are sulflde oxidizers, such as the giant tube worms Riftta pachyptila), which reach lengths of 1 m. As shown in Figure 19.19, the tube worms are essentially a closed sac, having no mouth, digestive system, or other means of processing particulate food. 

Internal structure of the tube worm Riftia pachyptila. (a) Oxygen, sulfide, and carbon dioxide are absorbed through the plume filaments and transported In the blood to the cells of the trophosome. (b) The chemicals are absorbed into these cells, which contain dense colonies of sulfur bacteria, where they are converted to organic compounds and (c) passed back into the circulatory system to act as an energy source for the worms. Source-. From Childress, J. J., et al. (1987). Scientific American, 256, 114-121. 

Moderate gas fluxes result in gas hydrate mounds, dense diverse chemo-synthetic communities, (Beggiatoa, tube worms, clams), and moderately degraded hydrocarbons. 

Pogonophoran Tube Worms, Bathymodiolid Mussels, Lucinid Clams) Moderately Biodegraded Hydrocarbons... 

A variety of other amino acid- or peptide-based cues also induce larval settlement and metamorphosis. For example, larvae of the sand dollar Dendraster excentricus settle and metamorphose in response to (1) a peptide-based cue from sand associated with adults, and (2) to water conditioned by adults.135 137 The nudibranch Adalaria proxima is induced to settle and metamorphose by a water-soluble-peptide-based cue from its bryozoan host Electra pilosa.138 139 A surface-associated peptide inducer has been proposed for the tube worm Phragmatopoma lapidosa californica140 but its role as a natural inducer remains to be defined. 

Pawlik, J.R., Chemical induction of larval settlement and metamorphosis in the reef-building tube worm Phragmatopoma californica (Polychaeta Sabellariidae), Mar. Biol., 91, 59, 1986. 

Toonen, R.J. and Pawlik, J.R., Settlement of the tube worm Hydroides dianthus (Polychaeta Serpul-idae) cues for gregarious settlement, Mar. Biol., 126, 725, 1996. 

Pawlik, J.R., Butman, C.A., and Starczak, V.R., Hydrodynamic facihtation of gregarious settlement of a reef-building tube worm, Science, 251, 421, 1991. 

Sabellaria alveolata, a reef-building tube worm from European waters, also settled in response to conspecific tube sand. However, S. alveolata did not metamorphose normally in response to any FFA, and an inducer from the tube sand of these animals was not isolated or identified.84 These larvae were much less discriminating in their choice of substrata than were those of Phragmatopoma lapidosa californica. Larvae of the nongregarious species Sabellaria floridensis did not metamorphose to any greater extent on conspecific tube sand than on control sand. Metamorphosis was also not enhanced upon exposure to FFA.83... 

Fatty acids have been implicated in the settlement and metamorphosis of the gregarious tube worm Phragmatopoma lapidosa californica, which settles in response to cues deposited in the tube sand cement, and two sea urchins, Pseudocentrotus depressus and Anthocidaris crassispina, which metamorphose in response to eicosapentaenoic acid extracted from the coralline red alga Corallina pilulifera. However, Jensen et al.87 provided good evidence that fatty acids were contaminants that... 

Pawlik, J. R. and Butman, C. A., Settlement of a marine tube worm as a function of current velocity interacting effects of hydrodynamics and behavior, Limnol. Oceanogr., 38, 1730, 1993. 

Pawlik, J. R. and Faulkner, D. J., Specific free fatty acids induce larval settlement and metamorphosis of the reef-building tube worm Phragmatopoma califomica (Fewkes), J. Exp. Mar. Biol. Ecol., 102, 301, 1986. 

In some cases, the nature of the chemical signal is known as well. Larvae of the tube worm Phragmatopoma californica undergo metamorphosis in response to a proteinaceous substance present in the tubes built by conspecific adults.95 Larvae of the sand dollar Dendraster excentricus... 

Robinson and colleagues (2003) explored the properties of rubisco from the bacterial endosym-biont of the giant tube worm Riftia pachyptila. Rubisco, from any source, catalyzes the reaction of either C02 (Fig. 20-7) or 02 (Fig. 20-20) with ribulose 1,5-bisphosphate. In general, rubisco reacts more readily with C02 than 02. The degree of selectivity (IT) can be expressed as... 

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