Annelid worm

Trivalent chromium was less effective than Cr+6 in reducing fecundity of Daphnia magna 44 pg Cr+VL vs. 10 pg Cr+6/L (USEPA 1980). Annelid worms (Tubifex sp.) accumulated about 1 mg total chromium/kg whole body during exposure for 2 weeks in sediments containing 175 mg ( T+3/kg, suggesting that benthic invertebrates have only a limited ability to accumulate chromium from sediments or clays (Neff et al. 1978). 

Copper in livers and muscles of Weddell seals was positively correlated with manganese (Szefer et al. 1994). In general, manganese and copper are positively correlated in tissues of marine vertebrates (Eisler 1984). Uptake of copper from copper-contaminated freshwater sediments by annelid worms is related to the amount of reducible manganese oxide in the sediments (Diks and Allen 1983). 

Polychaete annelid worms, marine England, 1984-86 near nuclear plant vs. control location Arenicola marina ... 

Animal Sources. The marine annelid worm Lumbrineris hetero-poda produces an insect toxin nereistoxin, 24, 4-N,N-dimethyl-amino-1,2-dithiolane (5 ). The mink MusteXa vison) affords 2,2-dimethylthietane, 14, and 3,3-dimethy1-1,2-dithiolane, 25 (28,63, 64), the ferret Musteta putoris) secretes 14, 25, cis- and trans-2,3-dimethylthietane, 2-propyl- and 2-pentyl-thietane, cis and trans-3,4-dimethyl-l,2-dithiolane, and 3-propyl-l,2-dithiolane (65), and the stoat (Mustela erminea) contains 2-ethyl-, 2-propyl-, and 2-pentyl-thietane, and 3-ethyl- and 3-propyl-l,2-dithiolane in its anal gland (5, ). These several thiaheterocycles from mustela species probably function as scent markers. 

While the hydra is almost immortal as a result of the continuous differentiation of its stem cell lines, other small invertebrates follow a very different course of development. Both the rotifers and the annelid worms (Fig. 1-14) tend to have a constant number of cells in the adult body. The entire developmental program is specified genetically in strict detail. 

The nervous system resembles that of the annelid worms, but it is not segmented. The brain is the dorsal ganglion, an accumulation of nerve cells located over the esophagus, which extend into a single ventral nerve cord. 

Of the 25 animal phyla, almost half are worms. Thus, it is not at all surprising that some worms contain toxins. The nemertines are a phylum of over 800 known species which resemble flatworms but are active predators on crustaceans and other worms. This phylum is exceptionally toxic among the various worm phyla. The Heteronemertine side possesses peptide toxins which appear to be only defensive, as these animals have no means of injecting a venom. The peptides include neurotoxins, which enhance excitability of nerve membranes, and cytolysins, which permeabilize and destroy cell membranes. Members of the Hoplonemertine class inject a venom into their prey using a mineralized stylet located in their proboscis, which is also used to immobilize the prey. Their toxins are alkaloids similar to nicotine which in minute amounts paralyze crustaceans and annelid worms and primarily activate nicotinic acetylcholine receptors. Another well-known worm toxin is nereistoxin, a disulfide-containing alkaloid which also binds to nicotinic... 

G. Wald, S. Rayport (1977). Vision in annelid worms. Science, 196,1434-1439. 

As noted earlier, three solutions to the problem of dioxygen transport have evolved hemoglobin (Hb), hemocyanin (He), and hemerythrin (Hr). Their remarkable distribution over plant and animal kingdoms is shown in Figure 4.8.The hemoglobins and myoglobins found in plants, snails, and vertebrates all appear to share a common, very ancient ancestor. There is some evidence now for a common ancestral hemocyanin.The appearance of hemerythrin in a few annelid worms is an evolutionary curiosity. These few words and the diagram will... 

Hemoglobins are the most evolutionarily diverse family of dioxygen carriers. They are found in some plants (e.g., leghemoglobin in the nitrogen-fixing nodules of legumes), many invertebrates (including some insect larvae), crustaceans, molluscs (especially bivalves and snails), almost all annelid worms, and in all vertebrates with one possible exception, the Antarctic fish Cyclostomata. 

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