Xiphophorus

Fish avoid more vigorously the odor of predators that have fed on members of their species than that of those on different diets. For example, young Arctic chart avoid water from brown trout fed on Arctic chart and are less wary of that from pellet-fed trout (Hirvonen et ah, 2000). Prey fish also reduce their predator inspection behavior vis-a-vis predators that have eaten members of their own species. For instance, finescale dace, Phoxinus neogaeus, dash toward predators such as yellow perch, Percaflavescens, and withdraw. Dace inspect perch models less often if the model is accompanied by water from perch that had eaten dace than if accompanied hy water from perch on a swordtail, Xiphophorus hdleri, diet. Dace produce alarm pheromone, while swordtails do not. The Central American swordtails do not cooccur with finescale dace (Brown etal, 2001). 

More recently, an additional member of this family (NT-6) has been discovered in the fish Xiphophorus. The activities of this neurotrophin remain to be characterized in detail, but the spectrum of sensitive neurons appear to be similar to that of NGF. NT-6 is different from the other neurotrophins in that it appears that the mature molecule is not released from the producing cell instead, it remains associated with the cell surface (or with the extracellular matrix). 

Smirnova, G.P. (1967). Dependence of the thermoresistance of Xiphophorus helleri on the amount of consumed food (In Russian). Proceedings of All-Union Conference... 

Experimental and environmental oncology in fish has been under study for more than 40 years, and a number of favorites have made it to the forefront rainbow trout (Oncorhynchus mykiss), Xiphophorus spp. and medaka (Oryzias latipes) in the realm of tank-held experimental models. Likewise, there are naturally occurring epizootics of cancer that have proven to be worthy models of study including the English sole (Parophrys vetulus), mummichog (Fundulus heteroclitus) and shad (Dorosoma... 

DNA repair mechanisms in different Xiphophorus hybrids have also recently been investigated117 185. There is already considerable interest in understanding the molecular basis of the defects in human syndromes associated with deficiencies in... 

DNA repair, some associated with skin cancer19. Such disorders result from defects in nucleotide excision repair and are all genetically complex, with involvement of multiple genes. Here again, the Xiphophorus model offers a potential means of unraveling each of the many steps involved in these complex molecular events that underpin multifactorial phenotypes. 

Interspecific Xiphophorus hybrids known to produce heritable melanoma and other forms of cancer have thus become a well-established model in which the underlying molecular mechanisms are starting to be elucidated. In addition to the hereditary melanoma model, other hybrids are available that develop defined epithelial, mesenchymal and neuronal neoplasia following treatment with specific carcinogens these all offer the opportunity to study the molecular mechanisms responsible for the malignant phenotype obtained. 

Adam, D., J. Wittbrodt, A. Telling and M. Schartl. RFLP for an EGF-receptor related gene associated with the melanoma oncogene locus of Xiphophorus maculatus. Nucl. Acids Res. 16 7212-7214, 1998. 

Adam, D., N. Dimitrijevic and M. Schartl. Tumour suppression in Xiphophorus by an accidentally acquired promoter. Science 259 816 -819, 1993. 

Anders, F., M. Schartl, A. Barnekow and A. Anders. Xiphophorus as an in vivo model for studies on normal and defective control of oncogenes. Adv. Cancer Res. 42 191-275, 1984. 

Froschauer, A., C. Korting, W. Bernhardt, I. Nanda, M. Schmid, M. Schartl and J.-N. Volff. Genomic plasticity and melanoma formation in the fish Xiphophorus. Mar. Biotechnol. 3 S72-S80, 2001. 

Kazianis, S., L. Gan, L. Della Coletta, B. Santi, D.C. Morizot and R.S. Nairn. Cloning and comparative sequence analysis ofTP53 in Xiphophorus fish hybrid melanoma models. Gene 212 31-38, 1998. 

Malitschek, B., D. Fornzler and M. Schaitl. Melanoma formation in Xiphophorus a model system for the role of receptor tyrosine kinases in tumorigenesis. Bioessays 17 1017—1023, 1995. 

Maueler, W., F. Raulf and M. Schartl. Expression of proto-oncogenes in embryonic, adult, and transformed tissue of Xiphophorus. Oncogene 2 421-430, 1988. 

Maueler, W., A. Schartl and M. Schartl. Different expression patterns of oncogenes and proto-oncogenes in hereditary and carcinogen-induced tumors of Xiphophorus. Int. J. Cancer 55 288—296, 1993. 

Morizot, D.C., B.B. McEntire, L. Della Coletta, S. Kazianis, M. Schartl and R.S. Nairn. Mapping of tyrosine kinase gene family members in Xiphophorus melanoma model. Mol. Carcinog. 22 150-157, 1998. 

Naim, R.S., D.C. Morizot, S. Kazianis, A.D. Woodhead and R.B. Setlow. Nonmammalian models for sunlight carcinogenesis genetic analysis of melanoma formation in Xiphophorus hybrid fish. Photochem. Photobiol. 64 440-448, 1996. 

Nairn, R.S., S. Kazianis, L. Della Coletta, D. Trono, A.P. Butler, R.B. Walter and D.C. Morizot. Genetic analysis of susceptibility to spontaneous and UV-induced carcinogenesis in Xiphophorus hybrid fish. Mar. Biotechnol. 3 S24-S36, 2001. 

Walter, R.B., H.-M. Sung, R.D. Obermoeller, D.L. Mitchell, G.W. Intano and C.A. Walter. Relative base excision repair in Xiphophorus fish tissue extracts. Mar. Biotechnol. 3 S50—S60, 2001. 

Wellbrock, C., R. Lammers, A. Ullrich and M. Schartl. Association between the melanoma-inducing receptor kinase Xmrk and the sre family tyrosine kinases in Xiphophorus. Oncogene 10 2135—2143,1995. 

Wittbrodt, J.D., B. Adam, W. Malitschek, F. Maueler, F. Raulf, A. Telling, S.M. Robertson and M. Schartl. Novel putative receptor tyrosine kinase encoded by the melanoma-inducing Tu locus in Xiphophorus. Nature 341 415-421, 1989. 

F.E. Ahmed, R.B. Setlow (1993). Ultraviolet radiation-induced DNA damage and its photorepair in the skin of the platyfish Xiphophorus. Cancer Res., 53,2249-2255. 

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