Copepod

Few studies have been conducted on other invertebrate taxa but pentach-lorophenol exposure has been shown to affect daphnid reproductive capacity and sex steroid hormone metabolism and a high incidence of intersex has been observed in harpacticoid copepods near an Edinburgh sewage outfall. " ... 

The invertebrate phyla are often neglected in ecotoxicological testing protocols. A token invertebrate species such as the copepod Daphnia may be used to evaluate the effects on extremely diverse phyla. This neglects the diversity of biochemical and physiological functions that may render different phyla vulnerable to different classes of compound at different stages of their life cycles. 

Another possible example of endocrine disruption in situ relates to the hndings of Moore and Stevenson" of altered sex ratios and intersex harpacticoid copepods in the vicinity of Edinburgh s long sea sewage outfall. Intersexiiality is common in some crustaceans but is extremely rare in harpacticoid copepods. There was no relationship between the frequency of intersex and distance from the most contaminated sites and nor was there evidence that other benthic species had been adversely affected. Additional work is required to prove conclusively that endocrine disruption is involved in this case. 

Campbell and Herring (1990) examined eight species of copepods, and found that all of them contain coelenterazine (the luciferin) and a luciferase. In the Euaugaptilus species, over 90% of the luciferase was found in their legs, and over 40% of the total coelenterazine was found in the bodies. 

To this author, it seems unfortunate that the cloning of luciferases preceded the isolation of natural luciferases in the study of the luminous copepod, drawing interest away from the future study of natural copepod luciferases. 

The existence of coelenterazine in various nonluminous organisms suggests that some of the coelenterazine-dependent luminous organisms might obtain coelenterazine from their food, either as the sole source of this substance or as a supplement to the coelenterazine biosynthesized in the body. In the case of the hydrozoan Aequorea aequorea, it was reported that the medusa is unable to produce its own coelenterazine and is dependent on a dietary supply of this compound for its capability of bioluminescence (Haddock et al., 2001). The organisms that biosynthesize coelenterazine remain to be identified, but it seems to be a common opinion at present that at least copepods do make their own coelenterazine. According to Thomson etal. (1995), the shrimp Systellaspis debilis is capable of coelenterazine... 

Inouye and Shimomura, 1997). With Ptilosarcus luciferase, the luminescence intensity of e-coelenterazine is also significantly higher than that of coelenterazine. With other coelenterazine luciferases, however, the luminescence intensity of e-coelenterazine is generally lower than that of coelenterazine for example, the luminescence intensities of e-coeienterazine measured with the luciferases of the decapod shrimps, the jellyfish Periphylla, and the copepod Pleuromamma, were 50%, 4%, and 0.8%, respectively, in comparison with that of coelenterazine. Thus, the luminescence of coelenterazine catalyzed by Pleuromamma luciferase is suppressed by the addition of e-coelenterazine. 

Coelenterazine can be detected and measured with a coelenterazine luciferase, i.e. a luciferase specific to coelenterazine. As the coelenterazine luciferase, the luciferases from the sea pansy Renilla and the copepods Gaussia and Pleuromamma are commercially available. Certain kinds of decapod shrimps, such as Oplophoms and Heterocarpus, contain a large amount of luciferase, and the luciferases purified from them are most satisfactory for the assay of coelenterazine considering their high activities and high quantum yields. Even partially purified preparations of these luciferases are satisfactory for most measurements. The author routinely uses purified Oplophoms luciferase. 

Ballou, B., Szent-Gyorgyi, C., and Finley, G. (2000). Properties of a new luciferase from the copepod Gaussia princeps. 11th Int. Symp. on Biolumin. Chemilumin., Abstract p. 34. Asilomar, CA. 

Markova, S. V., et al. (2004). Cloning and expression of cDNA for a luciferase from the marine copepod Metridia longa. J. Biol. Chem. 279 3212-3217. 

Frost, R. W. (1987). Grazing control of phytoplankton stock in the open subarctic Pacific ocean a model assessing the role of mesozooplankton, particularly the large calanoid copepods Neocalanus spp. Mar. Ecol. Prog. Ser. 39, 49-68. 

Additionally, G. brevis can have deleterious effects on subsequent generations of herbivores. Copepod development was severely impaired when G. brevis-containing diets were administered. Feeding on these diets by adults resulted in offspring with impaired development past the first feeding stage [37]. Whether or not this effect is due to the Na+ channel activator brevetoxins (5) and (6) has not been addressed. 

The observed toxicity seems to depend strongly on the form of toxin exposure. In contrast to the findings obtained with dissolved toxins, no feeding responses or toxicity in copepods were observed when the diatom-toxin domoic... 

The above findings would challenge the classical view of marine food web energy flow from diatoms to fish by means of copepods if this defense would be an universal feature of diatoms. In field experiments monitoring diatom abundance (but not food uptake) and hatching success of copepods, only a few... 

The effects of decadienal (24) as well as of diatom extracts are not restricted to the reduction of copepod success. Low, micromolar concentrations of this compound also inhibits fertilization, embryogenesis, and hatching success in polychaetes and echinoderms. Crude diatom extracts as well as purified aldehydes inhibited these processes in a dose-dependent manner [80]. 

Hydrozoa, such as A. victoria, and Anthozoa both belong to the phylum Cnidaria. In addition, fluorescent proteins have been isolated from planktonic Copepods, which belong to the evolutionary distant phylum Arthropodia [14], This wide phylogenetic distribution of GFP-like proteins might implicate that these proteins developed early in evolution and hence that almost every animal taxon can potentially contain GFP homologs [1],... 

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