Newts

Phan-Thien N, Atkinson JD, Tanner RI (1978) J Non-Newt Fluid Mech 3 309... 

Astarita. G. J. Non-Newt. FluidMech. 4 (1979) 285. Scaleup problems arising with non-Newtonian fluids. 

Cooke, A. (1971). Selective predation by newts of tadpoles treated with DDT. Nature 229, 275-276. 

PI. 2.1B Amphibian AOS, surface of accessory neuroepithelium chemosensory strips divided by non-sensory ridges in lateral nasal sinus of Japanese Red-bellied Newt (iCyaops pyrrhogaster) SEM X 742, R = ridge with microvillous cells and G = groove with ciliated cells and cellular protrusions (from Jones et at., 1994). 

The pituitary, as well as the hypothalamic hormones, also contribute to VN development. A transient prolactin receptor (PRLR) is expressed in the late foetal rat. At El8, there is positive staining for this binding protein along the lumenal border the reaction is restricted to the medial (sensory) zone [Freemark et al, Fig. 6(d), 1996]. These sites possibly function in the detection of endogenous lactogenic ligands such as PL-I and PL-II. The VNORs also occupy microvillous sites in this area, but the precise developmental role of PRLR in the early AOS is unknown. The modulatory influence of prolactin is well established after puberty in mammals as a reproductive determinant (Chap. 5). In a more central role, it acts on the EOG recorded from the accessory area of the bulb in newts (Toyoda, 2000). 

Prevention of access is the least intrusive method since it need not have any irreversible consequences for the afferent pathway. The common entrance to both olfactory systems in newts is easily closed-off by plugging the nostrils (Kikuyama et al., 1997). A potentially reversible method threaded plugs into the NP canal of cats via the nasal cavity (Verbeme, 1980). This procedure produced a slight effect on male chemoinvestigation of urine and or scent marks. The advantages of avoiding tissue disturbance then, have to be offset by the lack of any estimate of the effectiveness of the blockade, especially if reversible. Tissue cement injections into the N-Pd can be applied to the larger... 

One well-analysed chemosignal system is that of the Red-bellied Newt (Cynops pyrrhogaster). Males of this species produce from the abdominal gland a semiochemical protein (sodefrin) with marked VNO activity as a female attractant (Kikuyama et al., 1997). Courtship displays of newts often contain tail-waving bouts, which direct cloacal or other secretions from the male toward female recipients (Fig. 3.1). A large stable molecule like sodefrin, alone or as part of a VNPr complex, is presumably suitable for such local transference. 

AOS responsiveness to hormonal influences is shown in the action of sodefrin on the lateral nasal sinus of newts (Cynops). The receptors in the accessory pocket are differentially affected by pituitary and ovarian hormones (Toyoda et al., 2000). The local EOG response to the pheromone (Fig. 5.1) was enhanced by the presence of prolactin or of estrogen alone. Receptor sensitivity increase is perhaps an alternate strategy to AOS receptor density increase several alternate routes of signal receptor adaptation (Fig. 7.1) have been hypothesised (Sorenson and Stacey, 1998). 

Iwata T., Umezawa K., Toyoda F., Takahashi N., et al. (1999). Molecular cloning of newt sex pheromone precursor cDNAs evidence for the existence of species-specific forms of pheromones. FEBS Lett 457, 400-404. 

Jones F., Pfeiffer C. and Asashima M. (1994). Ultrastructure of the olfactory organ of the newt, Cynops pyrrhogaster. Ann Anat 176, 269-275. 

Kikuyama S., Toyoda F., Ohmiya Y., Matsuda K., et al. (1995). Sodefrin a female-attracting peptide hormone in newt cloacal glands. Science 267, 1643-1645. 

Murakami S. and Arai Y. (1992). Origin of LHRH-neurons in Newts effect of olfactory placode ablation. Cell liss Res 269, 21-27. 

Toyoda F. and Kikuyama S. (2000). Hormonal influence on the olfactory response to a female-attracting pheromone, sodefrin, in the newt, Cynops pyrrhogaste. Comp Biochem Physiol [B] 126, 239-245. 

Yamamoto K., Kawai Y., Hayashi T., Ohe Y., et al. (2000). Silefrin, a sodefrin-like pheromone in the abdominal gland of the sword-tailed newt, Cynops ensicauda. FEBS Lett 472, 267-270. 

A predator eating a victim that has accumulated pesticides in its tissues may die from secondary pesticide poisoning. For example, newts died when they ate tadpoles poisoned by OCPs. Frogs may die as a result of eating poisoned caterpillars [85]. 

Holly EE, Venkataraman SK, Chambon F, Winter HH (1988) J Non-Newt Fluid Mech 27 17... 

Rapid-acting neurotoxin that inhibits sodium-ion channels in neural and muscular tissue. It does not affect the neuromuscular junction. It is colorless crystals or a white powder that is obtained from puffer fish (Arothron sp.), frogs, newts, dinoflagellates (Takifugu poecilonotus), and bacteria (Pseudoalteromonas tetraodonis). It is heat stable but darkens on heating above... 

The species dig holes at the bottom and slopes of lakes and canals, causing severe impacts on invaded ecosystems. In the Ebro River, the crayfish is considered responsible for the disappearance of native fauna such as newts, frogs, and the autochthonous crayfish. Furthermore, it affects economically the rice crops in the Delta [53]. 

Newt, Triturus cristatus, adults, held in tank with a zinc-plated base South African clawed frog, Xenopus laevis 200 to 3000 overa 7-day period Zinc-poisoned newts were lethargic, ate poorly, and had skin darkening prior to death. Zinc residues were elevated in kidney, brain, liver, and intestine, when compared to controls. The hippocampus region of the brain of poisoned newts contained zinc-rich cells 82... 

Supplee, W.C. 1963. Antagonistic relationship between dietary cadmium and zinc. Science 139 119-120. Taban, C.H., M. Cathieni, and P. Burkard. 1982. Changes in newt brain caused by zinc water-pollution. Experientia 38 683-685. 

Chlordane residue data for amphibians and reptiles are extremely limited. Maximum concentrations of chlordane isomers did not exceed 70 pg/kg FW of oxychlordane in eggs of the American crocodile, Crocodylus acutus, or 250 pg/kg FW in carcass of the common garter snake, Thamnophis sirtalis (Table 13.2). However, California newts, Tarichia torosa, taken near a lake treated with 10 pg/L technical chlordane had greatly elevated chlordane residues in liver and comparatively low concentrations in carcass, stomach, and stomach contents. After 14 days, livers contained about 34 mg/kg total chlordanes lipid weight — about 19% chlordanes, 9% nonachlors, and 6% chlor-denes (Albright et al. 1980). After 2.8 years, 98% of the total chlordanes was lost. 7ra .v-nonachlor was the most persistent component in newt liver, accounting for up to 55% of the total chlordanes in specimens collected 2.8 years after application (Table 13.2) (Albright et al. 1980). 

Frogs, Rana spp., Louisiana, 1978-79, chlordanes, muscle, whole body California newt, Tarichia torosa, liver, from lake sprayed with 10 pg technical chlordane/L, total chlordanes ND 10... 

Albright, L.J., P.C. Oloffs, and S.Y. Szeto. 1980. Residues in cutthroat trout (Salmo clarki) and California newts (Tarichia torosa) from a lake treated with technical chlordane. Jour. Environ. Sci. Health Part B. Pestic. Food Contam. Agric. Wastes 15 313-349. 

NEWT, Pleurodeles waltl Embryos and larvae exposed to visible light alone, ultraviolet radiation alone, BaP alone at 12.5-500 pg/L, or combinations Visible light alone, UV radiation alone, or BaP alone 27 had no toxic effects. Genotoxic effects were observed at 500 pg BaP/L plus visible light, or 25 pg BaP/L plus UV radiation... 

Fernandez, M. and J. L Haridon. 1994. Effects of light on the cytotoxicity and genotoxicity of benzo[a]pyrene and an oil refinery effluent in the newt. Environ. Molec. Mutagen. 24 124-136. 

Radiation adversely affects limb regeneration of amphibians, alters DNA metabolism, and increases the frequency of chromosomal aberrations and liver lesions (Table 32.25). In some species of amphibians and reptiles, as in many mammals, mortality rates after acute exposure to radiation do not stabilize within 30 days — effectively invalidating the conventional LD50 (30-day postexposure) value. In the rough-skinned newt (Taricha granulosa), for example, the minimal LD50 dose at 200 days after irradiation was 2.5 Gy, compared with 350 Gy at 30 days (Willis and... 

Newt, Notophthalmus viridescens adults, single acute exposure of 20 Gy, one limb shielded or 22 Gy, whole body, no limbs shielded Frog, Rana sp., single acute exposure Forelimb regeneration completely suppressed when limbs to be amputated were irradiated directly. Irradiated limbs had severe and protracted inflammation, with total resorption of the affected limbs in 85% of the cases. Shielded limbs subsequently amputated had delays — but not suppression — in rate of forelimb regeneration and skin graft rejection 4... 

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