The Experts below are selected from a list of 2010 Experts worldwide ranked by ideXlab platform
Ingming Chiu - One of the best experts on this subject based on the ideXlab platform.
-
structure and stability of an acidic fibroblast growth factor from Notophthalmus viridescens
Journal of Biological Chemistry, 2002Co-Authors: A I Arunkumar, Ingming Chiu, Sampath Srisailam, T K S Kumar, Karuppanan Muthusamy Kathir, Han Min Wang, Gugang Chang, Chin YuAbstract:Abstract The three-dimensional solution structure of an acidic fibroblast growth factor (nFGF-1) from the newt (Notophthalmus viridescens) is determined using multidimensional NMR techniques. Complete assignment of all the atoms (1H, 15N, and 13C) has been achieved using a variety of triple resonance experiments. 50 structures were calculated using hybrid distance geometry-dynamical simulated annealing technique with a total of 1359 constraints. The atomic root mean square distribution for the backbone atoms in the structured region is 0.60 A. The secondary structural elements include 12 β-strands arranged antiparallely into a β-barrel structure. The protein (nFGF-1) exists in a monomeric state upon binding to the ligand, sucrose octa sulfate (SOS), in a stoichiometric ratio of 1:1. The SOS binding site consists of a dense cluster of positively charged residues located at the C-terminal end of the molecule. The conformational stabilities of nFGF-1 and its structural and functional homologue from the human source (hFGF-1) are drastically different. The differential stabilities of nFGF-1 and hFGF-1 are attributed to the differences in the number of hydrogen bonds and the presence of solvent inaccessible cavities in the two proteins.
-
Cloning and interspecies comparisons of three newt (Notophthalmus viridescens) fibroblast growth factor receptor sequences
Molecular and Cellular Biochemistry, 1997Co-Authors: Matthew L Poulin, Mary Jane Botelho, Ingming ChiuAbstract:We report the nucleotide sequences of two fibroblast growth factor receptor (FGFR) cDNAs, FGFR1 and FGFR3, from the newt species Notophthalmus viridescens. These two cDNA sequences and a previously published newt FGFR cDNA, FGFR2, were used to derive the amino acid sequences which were then compared with their homologues from other species. This comparison shows that the intracellular tyrosine kinase domain is highly conserved across the species examined with the second half of the domain slightly more conserved than the first half. The 3′ portion of the carboxyl terminal tail is not very highly conserved. The comparison of the extracellular portion of FGFR2 shows a high degree of conservation among the Ig-like domains and a low degree of conservation in the region that links the third Ig-like domain with the transmembrane domain. (Mol Cell Biochem 175: 11–19, 1997)
-
nucleotide sequences of two newt Notophthalmus viridescens fibroblast growth factor receptor 2 variants
Biochimica et Biophysica Acta, 1994Co-Authors: Matthew L Poulin, Ingming ChiuAbstract:Abstract The FGF receptor tyrosine kinase family consists of four members. We report the sequence of two newt (Notophthalmus viridescens) FGFR2 cDNAs which were isolated from a forelimb blastema cDNA library and represent the newt cognates of two different isoforms of FGFR2, one homologous to bek the other to the KGFR.
Matthew J. Parris - One of the best experts on this subject based on the ideXlab platform.
-
rapid change in life cycle polyphenism across a subspecies boundary of the eastern newt Notophthalmus viridescens
Journal of Herpetology, 2011Co-Authors: Mizuki K. Takahashi, Yukiko Y Takahashi, Matthew J. ParrisAbstract:Abstract Life-cycle polyphenism has been hypothesized to facilitate ecological speciation in salamanders. A recent study demonstrated that the Eastern Newt (Notophthalmus viridescens) subspecies genetically differ in expression of life-cycle polyphenism. However, we currently lack direct evidence that the life-history divergence among the newt subspecies is associated with the suggested ecological parameters, namely availability of wetlands and suitable terrestrial habitats. To test such associations, we examined life-history traits of two subspecies, Notophthalmus viridescens viridescens and Notophthalmus viridescens dorsalis, across the subspecies boundary, which corresponds with changes in those ecological parameters between the Piedmont Plateau and the Coastal Plain. We reared larval newts derived from the two focal subspecies across the contact zone in outdoor mesocosms under two different hydroperiod treatments (three-month drying and permanent water). We found striking genetically based differences...
-
on the role of sexual selection in ecological divergence a test of body size assortative mating in the eastern newt Notophthalmus viridescens
Biological Journal of The Linnean Society, 2010Co-Authors: Yukiko Y Takahashi, Mizuki K. Takahashi, Matthew J. ParrisAbstract:Speciation processes initiated by divergent selection often fail to complete; yet, how sexual selection is involved in the progress of ecological speciation is rarely understood. Intraspecific body-size variation affects mate preference and male–male competition, which can consequently lead to assortative mating based on body size. In the present study, we tested the importance of body size difference in the potential of assortative mating between the two eastern newt subspecies, larger Notophthalmus viridescens viridescens and smaller Notophthalmus viridescens dorsalis. Through differential expression of life-cycle polyphenism, these two subspecies are adapted to contrasting environments, which has likely led to the subspecific body-size difference. We found that males of both subspecies preferred larger females of N. v. viridescens as mates presumably because of the fecundity advantage of larger females. On the other hand, no evidence of female choice was found. Larger males of N. v. viridescens exhibited greater competitive ability and gained primary access to larger females of their own kind. However, smaller males were able to overcome their inferior competitive ability by interfering with larger males' spermatophore transfer and sneakily mating with larger females. Thus, the subspecific body-size difference importantly affected sexual selection processes, resulting in nonrandom but not completely assortative mating patterns between the larger and smaller subspecies. Although life-cycle polyphenism facilitates the intraspecific ecological divergence within N. v. viridescens sexual selection processes, namely smaller males' mate preference for larger females and sexual interference during spermatophore transfer, may be halting completion of the ecological speciation. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 884–897.
-
On the role of sexual selection in ecological divergence: a test of body‐size assortative mating in the eastern newt Notophthalmus viridescens
Biological Journal of the Linnean Society, 2010Co-Authors: Mizuki K. Takahashi, Yukiko Y Takahashi, Matthew J. ParrisAbstract:Speciation processes initiated by divergent selection often fail to complete; yet, how sexual selection is involved in the progress of ecological speciation is rarely understood. Intraspecific body-size variation affects mate preference and male–male competition, which can consequently lead to assortative mating based on body size. In the present study, we tested the importance of body size difference in the potential of assortative mating between the two eastern newt subspecies, larger Notophthalmus viridescens viridescens and smaller Notophthalmus viridescens dorsalis. Through differential expression of life-cycle polyphenism, these two subspecies are adapted to contrasting environments, which has likely led to the subspecific body-size difference. We found that males of both subspecies preferred larger females of N. v. viridescens as mates presumably because of the fecundity advantage of larger females. On the other hand, no evidence of female choice was found. Larger males of N. v. viridescens exhibited greater competitive ability and gained primary access to larger females of their own kind. However, smaller males were able to overcome their inferior competitive ability by interfering with larger males' spermatophore transfer and sneakily mating with larger females. Thus, the subspecific body-size difference importantly affected sexual selection processes, resulting in nonrandom but not completely assortative mating patterns between the larger and smaller subspecies. Although life-cycle polyphenism facilitates the intraspecific ecological divergence within N. v. viridescens sexual selection processes, namely smaller males' mate preference for larger females and sexual interference during spermatophore transfer, may be halting completion of the ecological speciation. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 884–897.
Dietrich Mebs - One of the best experts on this subject based on the ideXlab platform.
-
revisited failure of tetrodotoxin to protect red spotted newts Notophthalmus viridescens from endoparasites
Toxicon, 2020Co-Authors: Dietrich Mebs, Mari Yotsuyamashita, Katharina Hartmann, Christine Elbert, Richard Zehner, Stefan W ToennesAbstract:Abstract Red-spotted newts, Notophthalmus viridescens, contain tetrodotoxin (TTX) and its analogue 6-epiTTX in variable concentrations. In a follow-up study, newts were sampled from a pond in Pennsylvania, USA, in 2010, 2014, and 2018. Their toxin levels were assayed by liquid-chromatography-fluorescence detection (LC-FLD), and assessment of their infection with endoparasites such as nematodes and helminths was performed by histological examination of internal organs. In the 2010 and 2014 samples, average prevalence of parasite infection was 53 and 60%, respectively, but reached 100% in the 2018 sample, where metacercaria stages of the digenean trematode genus Australapatemon/Apatemon (family: Strigeidae) were predominant causing severe tissue damage in liver and kidney. Mean values of TTX and 6-epiTTX were not significantly different in parasitized or parasite-free newts over the study period, confirming previous findings that host toxicity and parasite load are not negatively correlated. Whereas the role of TTX in defence against predators is undisputed, its efficacy to prevent parasitic infections is less obvious. Toxin-resistance of various metazoan parasites may promote their widespread occurrence in poisonous newts.
-
tetrodotoxin does not protect red spotted newts Notophthalmus viridescens from intestinal parasites
Toxicon, 2012Co-Authors: Dietrich Mebs, Mari Yotsuyamashita, Hanns M. Seitz, Osamu ArakawaAbstract:Abstract Tetrodotoxin (TTX) and its analogue 6- epi TTX had been detected in the red-spotted newt, Notophthalmus viridescens . Thirty specimens of a population from Pennsylvania, USA were histologically examined for the presence of intestinal parasites. More than 50% were found to be infected with nematodes (Trichocephalidae), trematodes or cestodes (Pseudophyllidae). The mean values of TTX and 6- epi TTX in parasitized and in non-parasitized newts were not significantly different. Using a monoclonal antibody-based immunoenzymatic technique, TTX was localized in the intestinal tissue as well as in the parasites indicating that they accumulate the toxin and suggesting that TTX and 6- epi TTX are not providing protection from parasites to the newts.
-
tissue distribution of tetrodotoxin in the red spotted newt Notophthalmus viridescens
Toxicon, 2010Co-Authors: Dietrich Mebs, Osamu Arakawa, Mari YotsuyamashitaAbstract:High levels of tetrodotoxin (TTX) and of its analogue 6-epi-tetrodotoxin have been detected in skin and liver extracts of the red-spotted newt Notophthalmus viridescens assayed by a post-column fluorescent-HPLC system. Using a monoclonal antibody-based immunoenzymatic technique, TTX was localized in the granular glands of the epidermis as well as in the muscle layer between the muscle fibres, but also in most organs suggesting that TTX is stored in the whole body of the newt and is secreted by skin glands.
-
the levels of tetrodotoxin and its analogue 6 epitetrodotoxin in the red spotted newt Notophthalmus viridescens
Toxicon, 2001Co-Authors: Mari Yotsuyamashita, Dietrich MebsAbstract:Abstract Tetrodotoxin (TTX) and its analogue 6- epi TTX were detected in 11–12 specimens of the red-spotted newt, Notophthalmus viridescens , by a post-column fluorescent-HPLC system and by LC/MS in selected ion monitoring mode. TTX levels varied considerably among individuals from low (less than 0.15 μg TTX/g newt) to high concentrations (23.5 μg TTX/g newt), while 6- epi TTX was found to be a minor constituent in all specimens.
Mizuki K. Takahashi - One of the best experts on this subject based on the ideXlab platform.
-
rapid change in life cycle polyphenism across a subspecies boundary of the eastern newt Notophthalmus viridescens
Journal of Herpetology, 2011Co-Authors: Mizuki K. Takahashi, Yukiko Y Takahashi, Matthew J. ParrisAbstract:Abstract Life-cycle polyphenism has been hypothesized to facilitate ecological speciation in salamanders. A recent study demonstrated that the Eastern Newt (Notophthalmus viridescens) subspecies genetically differ in expression of life-cycle polyphenism. However, we currently lack direct evidence that the life-history divergence among the newt subspecies is associated with the suggested ecological parameters, namely availability of wetlands and suitable terrestrial habitats. To test such associations, we examined life-history traits of two subspecies, Notophthalmus viridescens viridescens and Notophthalmus viridescens dorsalis, across the subspecies boundary, which corresponds with changes in those ecological parameters between the Piedmont Plateau and the Coastal Plain. We reared larval newts derived from the two focal subspecies across the contact zone in outdoor mesocosms under two different hydroperiod treatments (three-month drying and permanent water). We found striking genetically based differences...
-
on the role of sexual selection in ecological divergence a test of body size assortative mating in the eastern newt Notophthalmus viridescens
Biological Journal of The Linnean Society, 2010Co-Authors: Yukiko Y Takahashi, Mizuki K. Takahashi, Matthew J. ParrisAbstract:Speciation processes initiated by divergent selection often fail to complete; yet, how sexual selection is involved in the progress of ecological speciation is rarely understood. Intraspecific body-size variation affects mate preference and male–male competition, which can consequently lead to assortative mating based on body size. In the present study, we tested the importance of body size difference in the potential of assortative mating between the two eastern newt subspecies, larger Notophthalmus viridescens viridescens and smaller Notophthalmus viridescens dorsalis. Through differential expression of life-cycle polyphenism, these two subspecies are adapted to contrasting environments, which has likely led to the subspecific body-size difference. We found that males of both subspecies preferred larger females of N. v. viridescens as mates presumably because of the fecundity advantage of larger females. On the other hand, no evidence of female choice was found. Larger males of N. v. viridescens exhibited greater competitive ability and gained primary access to larger females of their own kind. However, smaller males were able to overcome their inferior competitive ability by interfering with larger males' spermatophore transfer and sneakily mating with larger females. Thus, the subspecific body-size difference importantly affected sexual selection processes, resulting in nonrandom but not completely assortative mating patterns between the larger and smaller subspecies. Although life-cycle polyphenism facilitates the intraspecific ecological divergence within N. v. viridescens sexual selection processes, namely smaller males' mate preference for larger females and sexual interference during spermatophore transfer, may be halting completion of the ecological speciation. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 884–897.
-
On the role of sexual selection in ecological divergence: a test of body‐size assortative mating in the eastern newt Notophthalmus viridescens
Biological Journal of the Linnean Society, 2010Co-Authors: Mizuki K. Takahashi, Yukiko Y Takahashi, Matthew J. ParrisAbstract:Speciation processes initiated by divergent selection often fail to complete; yet, how sexual selection is involved in the progress of ecological speciation is rarely understood. Intraspecific body-size variation affects mate preference and male–male competition, which can consequently lead to assortative mating based on body size. In the present study, we tested the importance of body size difference in the potential of assortative mating between the two eastern newt subspecies, larger Notophthalmus viridescens viridescens and smaller Notophthalmus viridescens dorsalis. Through differential expression of life-cycle polyphenism, these two subspecies are adapted to contrasting environments, which has likely led to the subspecific body-size difference. We found that males of both subspecies preferred larger females of N. v. viridescens as mates presumably because of the fecundity advantage of larger females. On the other hand, no evidence of female choice was found. Larger males of N. v. viridescens exhibited greater competitive ability and gained primary access to larger females of their own kind. However, smaller males were able to overcome their inferior competitive ability by interfering with larger males' spermatophore transfer and sneakily mating with larger females. Thus, the subspecific body-size difference importantly affected sexual selection processes, resulting in nonrandom but not completely assortative mating patterns between the larger and smaller subspecies. Although life-cycle polyphenism facilitates the intraspecific ecological divergence within N. v. viridescens sexual selection processes, namely smaller males' mate preference for larger females and sexual interference during spermatophore transfer, may be halting completion of the ecological speciation. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 884–897.
Matthew L Poulin - One of the best experts on this subject based on the ideXlab platform.
-
Cloning and interspecies comparisons of three newt (Notophthalmus viridescens) fibroblast growth factor receptor sequences
Molecular and Cellular Biochemistry, 1997Co-Authors: Matthew L Poulin, Mary Jane Botelho, Ingming ChiuAbstract:We report the nucleotide sequences of two fibroblast growth factor receptor (FGFR) cDNAs, FGFR1 and FGFR3, from the newt species Notophthalmus viridescens. These two cDNA sequences and a previously published newt FGFR cDNA, FGFR2, were used to derive the amino acid sequences which were then compared with their homologues from other species. This comparison shows that the intracellular tyrosine kinase domain is highly conserved across the species examined with the second half of the domain slightly more conserved than the first half. The 3′ portion of the carboxyl terminal tail is not very highly conserved. The comparison of the extracellular portion of FGFR2 shows a high degree of conservation among the Ig-like domains and a low degree of conservation in the region that links the third Ig-like domain with the transmembrane domain. (Mol Cell Biochem 175: 11–19, 1997)
-
nucleotide sequences of two newt Notophthalmus viridescens fibroblast growth factor receptor 2 variants
Biochimica et Biophysica Acta, 1994Co-Authors: Matthew L Poulin, Ingming ChiuAbstract:Abstract The FGF receptor tyrosine kinase family consists of four members. We report the sequence of two newt (Notophthalmus viridescens) FGFR2 cDNAs which were isolated from a forelimb blastema cDNA library and represent the newt cognates of two different isoforms of FGFR2, one homologous to bek the other to the KGFR.
