Worm Comparisons

Segmented worms are much more advanced and complex than flatworms. The digestive systems of flatworms are one-way tubes sandwiched between two body walls. However, segmented worms have a space between their two body walls called the body cavity, or coelom, that represents an important evolutionary advance, one that provides a place for the body s internal organs. In segmented worms, organs are held in their proper places inside the coelom by a membrane, the peritoneum. 

All animals with coeloms are equipped with one set of muscles around the body wall and another set around the digestive system. The body wall muscles help the animal move about, while the digestive system 

Segmentation is an advance in animal evolution because segmented animals can increase in size by adding more body portions. In addition, segments can become specialized to carry out certain jobs. Flatworms are therefore limited in size as well as in the degree of specialization they can reach because they lack segments. 

Segmented worms have much more advanced digestive systems than flatworms do. A flatworm has one opening, a mouth, for food and wastes. A segmented worm has two openings, a mouth at one end and an anus at the other. The mouth opens to an esophagus that leads to a muscular pharynx. 

The evolutionary advancements from flat-worms to segmented worms are reflected in other animals such as mollusks and crustaceans, as well as in vertebrates. The segmented worms, although still evolutionarily simple, provided the groundwork from which further advancement evolved. 

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Pratt, D., Armes, L.G., Elagemen, R., Reynolds, V., Boisvenue, R. and Cox, G.N. (1992a) Cloning and sequence comparison of four distinct cysteine proteases expressed by Haemonchus contortus adult worms. Molecular and Biochemical Parasitology 51, 209-218. 

Anderson, S.L., F.L. Harrison, G. Chan, and D.H. Moore II. 1990. Comparison of cellular and whole-animal bioassays for estimation of radiation effects in the polychaete worm Neanthes arenaceodentata (Poly-chaeta). Arch. Environ. Contam. Toxicol. 19 164-174. 

Gandhi, T.K., Zhong, J., Mathivanan, S., Karthick, L., Chandrika, K.N., Mohan, S.S., Sharma, S., Pinkert, S., Nagaraju, S., Perias-wamy, B., et al, (2006) Analysis of the Human Protein Interactome and Comparison with Yeast, Worm and Fly Interaction Datasets. Nat Genet, 38, 285-293. 

Hartmann S observed that the worm traces are depleted in Mn, Ni, Cu, and Zn in comparison to the surrounding sediment. His opinion is that the decomposition of organic matter cannot lower the redox potential so far that dissolution of manganese takes place, except in locally limits) patches where organic matter is higher because of bioturbation. 

In contrast, if rigid chain molecules are of a rod-like shape (for a worm-like model x— 0), there is no conformational polydispersity in the assembly and comparison of Eqs. (61) and (62) gives G = 0.5. This is close to the value of G for a kinetically rigid (Jaussian coil both for weak (G = 0.667) and strong (G = 0.504) hydrodynamic interactions. 

A technique for visualizing the dynamics should allow for the comparison of dynamical relationships. These comparisons should include factors such as inherent variability between replicates or samples and an indication of the rate of change in variables. We have developed a method for this purpose which we call "space-time worms."... 

K. Worm-Leonhard, K. Larsen, and K. J. Jensen, 4,6-O-benzylidene directed /i-mannosylalion without intermediate trfilate formation Comparison of trichloroacetimidate and DISAL donors in microwave promoted glycosylations under neutral conditions, J. Carbohydr. Chem., 26 (2007) 349-368. 

DANS-based comparisons of daf-22 and wild-type metabolite extracts revealed several partial structures representing compounds produced only by wild type but not daf-22 worms, including several previously unknown compounds. These compounds represented far <0.1% of the entire metabolite mixture and therefore further characterization through HSQC or HMBC was not possible based on spectra of the unfractionated metabolite extracts. However, the differentially produced compounds were easily identified after partial... 

Comparison of experimental force for 97 kilobase >.-DNA dimers with the worm-like chain model [solid curve is Eq. (2,119) with = 33 pm and b — 100 nm]. The dotted curve corresponds to the Langevin function of the freely jointed chain model [Eq. (2.112)]. Data are from R. H. Austin et al., Phys. Today, Feb.—... 

Euling and Ambros 1996 Riddle 1988 Wadsworth and Riddle 1988), show considerable level of this mRNA (Fig. la and b). hi accord with thymidylate synthase specific activity, the enzyme mRNA level persists in dauer larvae for at least 6 weeks (Table 1 cf. Fig. 1). Additionally, comparison of the enzyme activity, enzyme protein and mRNA levels in adult worms, and LI, L3 and dauer larvae, shows only the enzyme protein and mRNA patterns (Table 1, Fig. 1, Results) to be correlated. Interestingly, the enzyme activity pattern parallels the two former patterns only with LI, L3 and dauer larvae, with the enzyme activity level in adult forms being low, relative to both mRNA and enzyme protein levels. The latter points to some regulation of enzyme protein expression and activity during the development. Of note is that T. spiralis thymidylate synthase mRNA levels showed no differences between adults, newborns and muscle larvae, with the enzyme specific activities in adults and muscle larvae also being comparable (Table 1, Fig. 1). 

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