effects of neurotransmitters upon the discharge of secretory product from the cutaneous glands of the red-spotted newt. | the effects of sympathetic and parasympathetic agonists and antagonists on discharge of secretory product by the granular and mucous glands were examined in the red-spotted newt, notopthalmus viridescens viridescens. observations were made also on the south african clawed toad. xenopus laevis, the grass frog, rana pipiens, and the crested newt, triturus cristatus. in contrast to the granular glands of the south african clawed toad and the grass frog, which were stimulated by alpha-adrenergic age ... | 1977 | 21937 |
polyfunctional antigen-binding specificity in hapten-carrier responses of the newt, triturus viridescens. | | 1975 | 53990 |
a portion of all major classes of histone messenger rna in amphibian oocytes is polyadenylated. | ovaries of the amphibian triturus viridescens contain a considerable amount of 7 to 12 s rna which fractionates with poly(a)+ rna on oligo(dt)-cellulose column chromatography and directs the synthesis of all five classes of histones in a wheat germ cell-free system. the polyadenylate tracts associated with this 7 to 12 s poly (a)+ rna are heterogeneous in length, ranging from approximately 60 to 120 nucleotides. partially purified subfractions of histone mrna templates were isolated from this rn ... | 1978 | 564902 |
visualization of bispecific antigen-binding in immunized splenic lymphocytes of the newt, triturus viridescens. | | 1978 | 640113 |
nerve trophic effects: an in vitro assay for factors involved in regulation of protein synthesis in regenerating amphibian limbs. | we have developed a rapid sensitive test for factors that mimic the trophic effects of nerves by maintaining normal rates of protein synthesis in denervated forelimb blastemata of adult newts (notophthalmus viridescens). rates of protein synthesis in secondary blastemata are similar. however, after they are denervated and explanted into organ culture the rates of protein synthesis first increase and later fall below control values. similar changes occur after denervation in vivo. the alterations ... | 1978 | 712346 |
ribosomal rna synthesis in the eastern north-american newt, notophthalmus viridescens. | ribosomal rna (rrna) synthesis, the initiation of which is an early major event during the transformation of iris into lens in the newt, was characterized in the tvi cell-line derived from the eastern north-american newt notophthalmus viridescens. employing the technique of polyacrylamide gel electrophoresis, molecular-weight measurements were made on newt rrnas using xenopus laevis and e. coli rrnas as standards. the molecular weights of n. viridescens 28s and 18s rrna were found to be 1.4 x 10 ... | 1977 | 838209 |
the effects of hydrocortisone and bacterial lipopolysaccharide on the anti-erythrocyte response in the spleens of adult triturus viridescens. | the effects of hydrocortisone (hc) and bacterial lipopolysaccharide (lps) have been tested separately and in combination, on the antigen-binding response of splenocytes of the newt. triturus viridescens immunized with horse erythrocytes (hrbc). the timing of the presentation of each was made relative to when challenge with either low (0.0025%) or high (25%) doses of the immunogen (hrbc) was effected. our results showed inhibition of both low and high dose responses by hc and additionally suggest ... | 1977 | 859006 |
the actions of restriction endonucleases on lampbrush chromosomes. | lampbrush chromosomes from oocytes of notophthalmus viridescens were dispersed in media containing restriction endonucleases isolated from haemophilus and e. coli. these endonucleases cleave duplex dnas at specific palindromic sequences of nucleotides, and several sensitive sites occur per micron of dna. the overwhelming majority of the lateral loops of lampbrush chromosomes are extensively fragmented by these endonucleases, but an occasional pair of loops is refractory. a notable example of loo ... | 1976 | 987047 |
on the diversity of sperm histones in the vertebrates. i. changes in basic proteins during spermiogenesis in the newt notophthalmus viridescens. | sperm histones display great variability in contrast to the conservation of most classes of somatic histones. to study this paradox, this series of papers examines the variation of histone patterns in the testis and sperm of vertebrates, particularly amphibians and reptiles, and attempts to relate such variation to genetically based sex determination as hypothesized by bloch [genetics supplement 61, 93 (1969)]. in the present study we have investigated spermiogenesis in the newt notophthalmus vi ... | 1976 | 1010162 |
identification of the lampbrush chromosome loops which transcribe 5s ribosomal rna in notophthalmus (triturus) viridescens. | the loops which transcribe 5s ribosomal rna in lampbrush chromosomes of the newt, notophthalmus (triturus) viridescens, were identified by hybridizing purified 5s dna to nascent 5s rna in situ. the genes which code for 5s rna were found near the centromeres of chromosomes 1, 2, 6, and 7 by hybridizing iodinated 5s rna to denatured lampbrush and mitotic chromosomes in situ. these genes and their intervening spacer dna were isolated from xenopus laevis using sequential silver-cesium sulfate equili ... | 1975 | 1201684 |
patterns of dystrophin expression in developing, adult and regenerating tail skeletal muscle of amphibian urodeles. | the patterns of expression of dystrophin were investigated by indirect immunofluorescence and by immunoblotting in developing, adult and regenerating tail skeletal muscle of newts pleurodeles waltl and notophthalmus viridescens. in this study, a monoclonal antibody h-5a3 directed against the c-terminal region (residues 3357-3660) and a polyclonal antibody raised to the central domain (residues 1173-1738) of the chicken skeletal muscle dystrophin were used. western blot analysis showed that these ... | 1992 | 1295566 |
homeobox-containing genes in the newt are organized in clusters similar to other vertebrates. | in vertebrates, the majority of homeobox (hbox) genes are found in four clusters and this structural organization is believed to be of functional importance. many hbox genes sustain their expression in the appendages of the adult newt. to further understand their regulation, the genomic loci of four newt hbox genes (two from the human hbox (hox)-2 complex and two from the hox-3 complex) were analysed and compared with homologous loci in other vertebrates. notophthalmus viridescens hbox (nvhbox) ... | 1992 | 1351019 |
newt squamous carcinoma proves phylogenetic conservation of tumors as caricatures of tissue renewal. | although regeneration-competent newts like notophthalmus viridescens have been reported to be resistant to carcinogenesis, we have been able to induce transplantable epidermal squamous cell carcinomas with 10-20% incidence by implanting 20-methylcholanthrene s.c. into the scapular region, a tissue that cannot regenerate. as soon as 1 week after exposure to this carcinogen, malignant cells were present in the treated skin, and after 4 weeks, macroscopic tumors of infiltrating squamous carcinoma c ... | 1992 | 1516043 |
analysis of opsin mrna and protein expression in adult and regenerating newt retina by immunology and hybridization. | rod photoreceptor cells were analysed in adult and regenerating notophthalmus viridescens retinae using a combination of immunochemical and molecular biological approaches. monoclonal anti-rhodopsin antibody (rho-4d2) labelled rod but not cone photoreceptors in adult newt retinae. the antibody bound to the entire cell body, from the synaptic ending through to the outer segment, as examined by light and electron immunocytochemistry. the antibody labelled two bands of 35 and 56 kda in western blot ... | 1992 | 1532825 |
amphibian prolactins: activity in the eft skin transepithelial potential bioassay. | the effects of purified prolactins isolated from frogs (fprl; rana catesbeiana) and newts (nprl; cynops pyrrhogaster) were compared with those of ovine prolactin (oprl) and thyrotropin releasing hormone (trh) in the eft (notophthalmus viridescens) skin transepithelial potential (tep) bioassay. at total doses as low as 0.4 micrograms/animal, both fprl and nprl were as effective as oprl in reducing eft skin tep. by contrast, trh at total doses as high as 400 micrograms/animal was ineffective in al ... | 1991 | 1908395 |
two dispersed highly repeated dna families of triturus vulgaris meridionalis (amphibia, urodela) are widely conserved among salamandridae. | two bamhi families of repeated sequences were characterized from the genome of the italian smooth newt, triturus vulgaris meridionalis (amphibia, urodela). the first family, which is divided into subfamilies, consists of tandemly arranged arrays whose basic repeat is around 398 bp long; these arrays are dispersed throughout the entire chromosome sets of the various species of triturus tested. moreover the family is widely conserved among salamandridae, being detected by genomic dna blotting of n ... | 1991 | 2009819 |
macrophage mobilization and morphology during lens regeneration from the iris epithelium in newts: studies with correlated scanning and transmission electron microscopy. | the lens was removed from both eyes of adult newts (notophthalmus viridescens), and the eyes were fixed in karnovsky's fixative every 2 days 0-20 days after operation. anterior half-eyes were prepared by standard procedures for scanning electron microscopy of the surface. before fixation, the posterior iris surface was cleaned of adhering vitreous mechanically with forceps or by treatment with bovine testicular hyaluronidase or with hyaluronidase and collagenase. some specimens were cryofracture ... | 1990 | 2392992 |
structure and expression of a newt cardio-skeletal myosin gene. implications for the c value paradox. | as part of our studies on the fate of the muscle lineage during amphibian limb regeneration, we have isolated genomic and cdna sequences from a myosin heavy chain in the newt (notophthalmus viridescens). notwithstanding the technical problems inherent in analysing the large newt genome, genomic and cdna sequences have been isolated and subjected to analysis by restriction mapping. northern hybridization, southern hybridization and dna sequencing. we believe these to be the first single copy newt ... | 1988 | 2459393 |
immunohistochemical localization of beta-endorphin-like material in the urodele and anuran amphibian tissues. | in the present study, we have localized for the first time beta-endorphin (beta-ep)-like material in the adult and larval urodele and anuran tissues using immunohistochemical techniques. in the adult notophthalmus viridescens and ambystoma mexicanum, strong immunoreactivity to beta-ep antisera was observed in the region of the intermediate lobe, the latter fluorescing as a discrete body. the fluorescence was confined to the periphery of the cells, while the nuclei and the immediately surrounding ... | 1989 | 2530130 |
localization of insulin, glucagon and somatostatin in the pancreas of the adult newt, notophthalmus viridescens. | the current study is designed to demonstrate the presence of immunoreactive insulin (iri), glucagon and somatostatin in the adult pancreas. methods include aldehyde fuchsin (af) staining and peroxidase anti-peroxidase (pap) immunochemical localization for light microscopy as well as protein a gold (pag) staining for scanning electron microscopy (sem) in conjunction with backscattered electron imaging (bei). our results show the presence of large clusters of af-positive cells within networks of h ... | 1989 | 2570473 |
primary cell culture and morphological characterization of ventricular myocytes from the adult newt, notophthalmus viridescens. | previous work has demonstrated that adult newt cardiac myocytes possess a proliferative ability in response to an experimentally induced injury, in vivo. this study describes an in vitro model in which the proliferative events of the adult cardiac myocyte may be studied. ventricles were minced and then enzymatically dissociated in a ca++- and mg++-free salt solution containing 0.5% trypsin and 625 u/ml of cls ii collagenase for 8 to 10 hours at 25 degrees c. enzyme digests were preplated and the ... | 1989 | 2658685 |
n-acetylglucosamine binding activity in extracts of adult newt skin. | 1. extracts of the dermis of the adult newt, notophthalmus viridescens, contain hemagglutination activity which is specifically inhibited by n-acetylglucosamine. 2. the activity is soluble and is associated with a doublet in sodium dodecyl sulfate polyacrylamide gels, the bands of which have relative molecular weights of 51,000 and 57,000 under both reducing and non-reducing conditions. 3. the activity requires magnesium but not calcium, cobalt, or manganese and is inhibited by barium. 4. the ac ... | 1988 | 2901319 |
position dependent expression of a homeobox gene transcript in relation to amphibian limb regeneration. | adult urodele amphibians such as the newt notophthalmus viridescens are capable of regenerating their limbs and tail by formation of a blastema, a growth zone of mesenchymal progenitor cells. in an attempt to identify genes implicated in specification of the regenerate, we screened a newt forelimb blastema cdna library with homeobox probes, and isolated and sequenced clones that identify a 1.8 kb polyadenylated transcript containing a homeobox. the transcript is derived from a single gene called ... | 1988 | 2907476 |
the substitution of carrier priming of helper function in the common american newt, notophthalmus viridescens by lectins and human lymphokines. | there is no clear evidence that helper function is thymus dependent in the common american newt, notophthalmus viridescens. here we test the capacity of concanavalin a, wheat germ agglutinin, human ril-1 and ril-2, reagents which stimulate t cell activities in other species, to substitute for carrier priming in the newt. cytofluorimetric analyses have been used to demonstrate specific il-2 receptor binding sites on newt splenocytes. competitive pre-binding with ril-2 tested whether anti-il-2 rec ... | 1988 | 2966462 |
bioengineered human growth hormone supports limb regeneration in the hypophysectomized newt notophthalmus viridescens. | it is well documented that growth hormone (gh) replacement therapy will restore normal limb regeneration to hypophysectomized adult newts. however, it is also known that the gh preparations used in previous reports were contaminated by other pituitary hormones shown to support regeneration when administered free of gh. the recent availability of bioengineered human gh was studied for its ability to restore the regenerative capacity to hypophysectomized newts. five days posthypophysectomy adult n ... | 1988 | 3199095 |
the antitumor drug 3-nitrobenzothiazolo(3,2-a)quinolinium chloride (nbq): effects on lens regeneration and interaction with dna of notophthalmus viridescens. | we have studied the effect of 3-nitrobenzothiazolo(3,2-a)quinolinium (nbq) on the regeneration of the lens in adult newt notophthalmus viridescens. nbq has marked cytotoxic effects in tumor cells, intercalates dna, and was found to enhance lens regeneration. newt liver dna was isolated, and the thermal denaturation temperature (tm) determined to be 76.6% +/- 0.8%. the g-c content was determined to be 44.0% +/- 0.4% and 45.0% +/- 0.1%. parameters of nbq binding to newt dna were determined by spec ... | 1987 | 3447920 |
hormonal facilitation in the release of sperm from the spermatheca of the red-spotted newt. | several neurotransmitters and hormones with potential to trigger a simultaneous contraction of the oviducts and the spermathecal myoepithelium were examined. saline (0.05 ml), or 0.05 ml saline plus acetylcholine (9 mg), norepinephrine (50 micrograms), arginine-vasotocin (25 units), prostaglandin f2 alpha (3 micrograms) were injected into the spermathecal region of female newts (n = 24 per group). the numbers of sperm present in the cloacae of prostaglandin-injected animals (107 +/- 30 sem) were ... | 1987 | 3470194 |
immunofluorescent detection and localization of thyroxine in blood of adult amphibians. | indirect immunofluorescent staining was used to detect and localize thyroxine (t4) in blood smears from different species of adult amphibians, namely, rana pipiens, rana catesbeiana, bufo marinus, xenopus laevis, and notopthalmus viridescens. fluorescence, indicative of t4, was observed in both plasma and erythrocytes (rbc) from all individuals of the five species studied. it was weak and diffuse in the plasma and in the cytoplasm of the rbc but was intense in the nuclei (especially the nuclear ... | 1986 | 3542699 |
influence of chromatographic fractions of extracts derived from bovine neural retina on newt (notophthalmus viridescens) lens regeneration in vitro. | removal of the ocular lens in adult newts (notophthalmus viridescens) is followed by a series of cellular events leading to regeneration of a new lens by cell type conversion of pigmented iris epithelial cells at the dorsal pupillary margin (yamada, curr. top. dev. biol. 2:247-283, 1967). following depigmentation and five to seven cell divisions, iris epithelial cells redifferentiate into lens fiber cells and synthesize crystallin proteins (yamada, curr. top. dev. biol. 2:247-283, 1967). this pr ... | 1987 | 3655682 |
the phylogeny of macrophage function: antigen uptake and degradation by peritoneal exudate cells of two amphibian species and caf1 mice. | equal numbers of thioglycollate mobilized peritoneal exudate cells (pec) of the newt, notophthalmus viridescens, the south african clawed toad, xenopus laevis, and caf1 mice were compared with respect to their capacity to take up and degrade soluble 14c-ovalbumin (ova). pec of the newt failed to take up the labeled antigen, while those of the toad incorporated only one-half as much as those of the mice. moreover, the toad pec degraded only 42% of the immunogen which was taken up, while pec of th ... | 1986 | 3757044 |
lens regeneration from cultured newt irises stimulated by retina-derived growth factors (edgfs). | it has been shown that lens regeneration from the iris of the newt notophthalmus viridescens is dependent on the presence of neural retinal tissue in organ culture and in vivo. the recent discovery of various eye-derived growth factors (edgfs) in the bovine retina [14] prompted us to investigate whether one of these factors may be involved in the stimulation of lens regeneration. dorsal irises were cultured for 20 days in serum-supplemented diluted eagle's medium. growth factors from bovine reti ... | 1986 | 3792708 |
role of the neural retina in newt (notophthalmus viridescens) lens regeneration in vitro. | removal of the lens from the eye of an adult newt (notophthalmus viridescens) is followed by regeneration of a new lens from the dorsal iris epithelial cells at the pupillary margin. this process is dependent upon the neural retina for its normal completion in vivo and in vitro. to examine the relationship between the retina and lens regeneration, we have conducted experiments that delimit the time period during which the retinal presence is critical (in vivo) and have investigated the influence ... | 1986 | 3794624 |
transport of sperm within the cloaca of the female red-spotted newt. | the transport of sperm in the cloaca and adjacent regions of the female red-spotted newt was examined. it was found that within 1 min after sperm were introduced into the vent, they progressed in a random pattern past the apertures of the spermatheca (the glandular, sperm storage organ that opens from the anterior roof of the cloaca) forward to the anterior end of the cloaca and on into the posterior regions of the hindgut and bladder. sperm did not enter the dorsal recess of the cloaca into whi ... | 1986 | 3806681 |
temporal analysis of the role of growth hormone in the initiation and maintenance of limb regeneration in the hypophysectomized newt notophthalmus viridescens. | this study was designed to investigate and determine for how long, after either hypophysectomy or the third (last) growth hormone injection (to previously hypophysectomized newts), the circulating and now declining titers of endogenous or exogenous hormone remained at a sufficient concentration to permit a morphologically normal forelimb regeneration response in the adult newt notophthalmus viridescens. to examine the declining levels of endogenous hormone (hormone withdrawal series [hw]), left ... | 1985 | 3981643 |
sensitivity and specificity of salamandrid integumental transepithelial potential to prolactin. | the effects of ovine prolactin (oprl), bovine growth hormone (bgh) and human placental lactogen (hpl) on in vivo integumental transepithelial potential (tep) were examined in two salamandrid urodeles, adult terrestrial-phase taricha granulosa and the juvenile red-eft stage of notophthalmus viridescens. tep in efts treated with 1.0 microgram oprl/2 days fell from 73.3 +/- 6.1 to 15.2 +/- 5.5 mv by day 7 (p less than 0.001), whereas the tep of efts treated with either 1.0 or 10 micrograms bgh/2 da ... | 1985 | 4018555 |
comparison of newt lens regeneration stimulating activity in preparations of mammalian thyrotropin and fibroblast growth factor purified by various methods. | irises of the newt notophthalmus viridescens will regenerate a new lens in organ culture in the presence of the bovine thyrotropin preparation nih-tsh-b8. it is not certain, however, whether thyrotropin itself is responsible for this stimulatory effect. to elucidate this problem further we compared the lens regeneration stimulating activity of thyrotropin preparations from several species, prepared by various methods. the lowest effective concentrations were approximately 3.0 micrograms ml-1 for ... | 1985 | 4092754 |
biosynthesis of thyrotropin releasing factor by newt (triturus viridescens) brain in vitro. isolation and characterization of thyrotropin releasing factor. | | 1974 | 4214528 |
effect of a highly purified growth hormone on limb regeneration in hypophysectomized newt, notophthalmus viridescens. | | 1974 | 4436625 |
cellular cooperation in hapten-carrier responses in the newt, triturus viridescens. | | 1973 | 4693837 |
action of human placental lactogen on second metamorphosis in the newt notophthalmus viridescens. | | 1973 | 4753366 |
isolation and characterization of viruses from the kidneys of rana pipiens with renal adenocarcinoma before and after passage in the red eft (triturus viridescens). | viruses were isolated from kidneys of normal and renal tumor-bearing vermont rana pipiens after subinoculation into red eft newts (triturus viridescens). organs of efts inoculated with viable cell suspensions from four of seven tumor-bearing kidneys yielded virus (lt-1, -2, -3, -4) when inoculated into th-1 (terrapene heart) cell culture. one tumor-bearing kidney also yielded virus (l-4) by direct inoculation into th-1 cells. an additional isolate (l-5) was obtained from 1 of 52 normal vermont f ... | 1968 | 4972302 |
fibrinogen and fibronectin as substrates for epidermal cell migration during wound closure. | pieces of glass coverslip coated with human fibronectin or human fibrinogen were implanted under one margin of a skin wound on adult newt (notophthalmus viridescens) hind limbs. in contrast to uncoated glass or glass coated with nest serum, bovine serum or bovine serum albumin, glass treated with either fibronectin or fibrinogen supported considerable epidermal cell migration. when optimal amounts of each protein were used, the amount of migration on fibrinogen-coated glass did not differ from t ... | 1983 | 6413516 |
the lipid composition of urodele myelin which lacks hydroxycerebroside and hydroxysulfatide. | the concentrations of cerebrosides and sulfatides were measured in the nervous systems of urodeles and related orders with a high performance liquid chromatographic technique. the peripheral and central nervous systems of all three urodele species, necturus maculosis (mud puppy, a salamander), notophthalmus viridescens (eastern red spot newt), and desmognathus ochropheus (mountain salamander), were found to be completely devoid of alpha-hydroxy fatty acid-containing cerebrosides and sulfatides. ... | 1984 | 6607972 |
in vitro transcription of cloned 5s rna genes of the newt notophthalmus. | recombinant plasmids that carried genes coding for 5s ribosomal rna of the newt, notophthalmus viridescens, were transcribed in vitro with extracts of xenopus laevis oocyte nuclei. plasmids containing multiple repeats of the 5s gene and spacer directed accurate transcription of 5s rna (120 bases). individual repeat units were recloned by inserting sau 3a restriction fragments into the bam hi site of plasmid pbr322. because each repeat was cut by the enzyme within the coding region, the inserts h ... | 1981 | 6945306 |
epidermal cell migration on collagen and collagen-derived peptides. | nucleopore filters coated with various genetic types of collagen and certain collagen-derived peptides were implanted under one margin of a skin wound on adult notophthalmus viridescens (newt) hind limbs. in contrast to their behaviour on untreated filters, epidermal cells migrated readily and to equal degrees on human type i, newt type i, bovine type ii, and bovine type iv collagen. denaturation had no effect on the ability of collagen to support migration and all three cyanogen bromide peptide ... | 1982 | 7153257 |
hormonal regulation of nuptial pads and tail fins in the female red-spotted newt. | | 1981 | 7262530 |
factors altering dna synthesis in the cardiac myocyte of the adult newt, notophthalmus viridescens. | to better understand the mechanisms governing the proliferation of cardiac myocytes it is important to identify the factors controlling this phenomenon, and to characterize their actions. dna synthesis was quantified in vitro in ventricular myocytes from the adult red-spotted newt, notophthalmus viridescens. ventricles were enzymatically separated and plated onto laminin. myocytes were fed modified l-15 medium with 10% fetal bovine serum, and were variously treated with transforming growth facto ... | 1994 | 7509264 |
noradrenergic and peptidergic innervation of the amphibian spleen: comparative studies. | spleens from representatives of the three amphibian orders were examined using sucrose-potassium phosphate-glyoxylic acid (spg) histofluorescence to detect catecholamines and immunocytochemistry to detect several neural antigens. nerve fibers are scattered throughout the spleens of adult salamanders (taricha torosa, notophthalmus viridescens, and ambystoma mexicanum). a less abundant but similarly diffuse pattern of innervation characterizes the spleen of the caecilian, typhlonectes sp. the sple ... | 1994 | 7539385 |
re-programming of expression of the kgfr and bek variants of fibroblast growth factor receptor 2 during limb regeneration in newts (notophthalmus viridescens). | we have previously shown, by in situ hybridization, that fibroblast growth factor receptor 2 (fgfr2) is present in the basal layer of wound epithelium during limb regeneration in newts (notophthalmus viridescens). in contrast, fgfr1 expression is observed throughout the blastema mesenchyme but is distinctly absent from the wound epithelium (poulin et al. [1993] development 119:353-361). sequence analysis revealed that we have isolated both the kgfr and bek variants of fgfr2. these two variants d ... | 1995 | 7626794 |
transcription of satellite 2 dna from the newt is driven by a snrna type of promoter. | the transcriptional promoter of satellite 2 from the eastern newt, notophthalmus viridescens, was analyzed by assaying the activity of deleted or mutated satellite 2 clones in xenopus laevis oocytes. two elements in the promoter were found to be important for transcription. these elements have sequences that are similar to the sequences of the octamer and the proximal sequence element of vertebrate snrna genes transcribed by rna polymerase ii. furthermore, the organization of these elements and ... | 1994 | 7984420 |
identification of an amphibian oocyte nuclear protein as a candidate for a role in embryonic dna replication. | monoclonal antibody b24/3 recognizes a nuclear protein of 104 kd in germinal vesicles of newt oocytes. immunohistostaining of oocytes at different stages of growth shows an accumulation of b24 protein throughout oogenesis. during development b24 protein is located inside embryonic cell nuclei from the onset of cleavage onwards. it gradually decreases from gastrulation and disappears at the tailbud stage. the nvb24 17.1 clone was isolated from an ovary expression library of the newt notophthalmus ... | 1993 | 8179995 |
heterogeneity in the expression of fibroblast growth factor receptors during limb regeneration in newts (notophthalmus viridescens). | two closely related fibroblast growth factor receptors, fgfr1 and fgfr2, have been cloned from a newt (notophthalmus viridescens) limb blastema cdna library. sequence analysis revealed that we have isolated both the bek and kgfr variants of fgfr2. these two variants differ only in the second half of the last of their three ig-like domains. the expression patterns of fgfr1 and fgfr2 during limb regeneration have been determined by in situ hybridization. during the preblastema stages of regenerati ... | 1993 | 8287792 |
retinoic acid stimulates the synthesis of a novel heat shock protein in the regenerating forelimb of the newt. | morphogenetic effects of retinoic acid (ra) on the urodele amphibian limb regenerate pattern have been well documented, but little is known regarding the mechanism of this action of ra at the molecular level. since exogenous ra, at concentrations sufficient to cause proximalization, represents a significant stress to newts and has been shown previously to elicit increased synthesis of heat shock proteins (hsps) in mouse embryo limb buds, we investigated the effects of this putative morphogen on ... | 1993 | 8329175 |
conserved sequence and functional domains in satellite 2 from three families of salamanders. | thirteen satellite 2 elements from ambystoma talpoideum and 16 from amphiuma tridactylum were cloned, sequenced, and compared with the satellite 2 consensus from notophthalmus viridescens. these elements have maintained a high degree of similarity during the 65-200 myr that the salamander families, represented by the three species, have been separated. the dna sequences of the consensus elements from a. talpoideum and a. tridactylum are 81% similar, and both are approximately 65% similar to the ... | 1993 | 8355598 |
local alteration of cortical actin in xenopus eggs by the fertilizing sperm. | rhodamine phalloidin (rph) staining was used to examine the microfilament organization of the xenopus laevis egg cortex during the early stages of fertilization. unactivated eggs possessed a cytochalasin b (cb)-insensitive rph-stained matrix that was reorganized upon egg activation and diminished in the presence of cb. xenopus laevis sperm caused a temporary local increase in rph staining on the xenopus cortex. in cb-treated eggs, the local increases of cortical rph staining later changed to a r ... | 1993 | 8507483 |
amphibian fgf-1 is structurally and functionally similar to but antigenically distinguishable from its mammalian counterpart. | recent studies have shown that fibroblast growth factors (fgf) play an important role in the diverse cellular mechanisms involved with vertebrate development. one system which has received a great deal of attention is the developing limb in part because of the extensive epithelial-mesenchymal interactions that take place during this process. because it closely parallels the developmental process of the limb and is a model for wound repair, the phenomenon of amphibian limb regeneration has been u ... | 1997 | 9086327 |
molecular cloning of the notophthalmus viridescens radical fringe cdna and characterization of its expression during forelimb development and adult forelimb regeneration. | larval and adult newts provide important experimental models to study limb development and regeneration. these animals have exceptional ability to regenerate their appendages, as well as other vital structures. our research examines the role of the fringe gene (fng) in the developing and regenerating adult newt forelimb. fringe codes for a secretory protein. it was first discovered in drosophila, and later homologues were isolated in xenopus laevis, chick and mouse. this gene has been highly con ... | 1999 | 10090152 |
cloning and neuronal expression of a type iii newt neuregulin and rescue of denervated, nerve-dependent newt limb blastemas by rhggf2. | urodele amphibians are the only vertebrates that can regenerate their limbs throughout their life. the critical feature of limb regeneration is the formation of a blastema, a process that requires an intact nerve supply. nerves appear to provide an unidentified factor, known as the neurotrophic factor (ntf), which stimulates cycling of blastema cells. one candidate ntf is glial growth factor (ggf), a member of the neuregulin (nrg) growth factor family. nrgs are both survival factors and mitogens ... | 2000 | 10770844 |
structure and stability of an acidic fibroblast growth factor from notophthalmus viridescens. | 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 ((1)h, (15)n, and (13)c) 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 back ... | 2002 | 12205097 |
genetic disparity and cancer induction by normal tissue implants in amphibia. | fifty percent of the implants of normal adult triturus cristatus kidney made into the forelimbs of immature but postmetamorphic xenopus laevis hosts initiated the formation of lymphosarcoma at the site of implantation. donor-host genetic disparity as it relates to the intensity of the reaction, when homografts, heterografts, and xenografts are compared, appears to be one of several factors which play a role in the post-embryonic induction of both lymphosarcomas in xenopus laevis and accessory li ... | 1964 | 14207463 |
interactions of bullfrog tadpole predators and an insecticide: predation release and facilitation. | the effect of a contaminant on a community may not be easily predicted, given that complex changes in food resources and predator-prey dynamics may result. the objectives of our study were to determine the interactive effects of the insecticide carbaryl and predators on body size, development, survival, and activity of tadpoles of the bullfrog (rana catesbeiana). we conducted the study in cattle tank mesocosm ponds exposed to 0, 3.5, or 7.0 mg/l carbaryl, and no predators or two red-spotted newt ... | 2003 | 14505025 |
chytridiomycosis impacts predator-prey interactions in larval amphibian communities. | despite ecologists increasingly recognizing pathogens as playing significant roles in community dynamics, few experimental studies have quantified patterns of disease impacts on natural systems. amphibians are experiencing population declines, and a fungal pathogen ( batrachochytrium dendrobatidis; chytridiomycota) is a suspected causal agent in many declines. we studied the effects of a pathogenic fungus on community interactions between the gray treefrog, hyla chrysoscelis, and eastern newts, ... | 2004 | 15235903 |
effects of exogenous fgf-1 treatment on regeneration of the lens and the neural retina in the newt, notophthalmus viridescens. | experiments were designed to compare the effects of recombinant newt fibroblast growth factor-1 (rnfgf-1) and recombinant human glial growth factor (rhggf) on lens and retina regeneration in the eyes of adult newts. both eyes were retinectomized and lentectomized. beginning 3 days after the operation, one eye was given either 0.1 microg of rnfgf-1 or 0.1 microg of rhggf in 1 microl of phosphate-buffered saline (pbs) per injection, three per week. contralateral operated eyes served as controls an ... | 2005 | 16161011 |
tail regeneration and ependymal outgrowth in the adult newt, notophthalmus viridescens, are adversely affected by experimentally produced ischemia. | spinal axons of the adult newt will regenerate when the spinal cord is severed or when the tail is amputated. ischemia and associated hypoxia have been correlated with poor central nervous system regeneration in mammals. to test the effects of ischemia on newt spinal cord regeneration, the spinal cord and major blood vessels of the newt tail were severed 2 cm caudal to the cloaca as a primary injury. this primary injury severely reduced circulation in the caudal direction for 7 days; by day 8, c ... | 2005 | 16254917 |
expression profiles of elastase1 (nvelastasei) and secretory leukocyte protease inhibitor (nvslpi) during forelimb regeneration in adult notophthalmus viridescens suggest a role in epithelial remodeling and delamination. | extracellular proteases and their inhibitors may regulate a number of important processes involved in forelimb regeneration in the adult newt, including epithelial remodeling, breakdown of extracellular matrix, and dedifferentiation. we have identified a newt homologue of human elastasei (nvelastasei) and its potential inhibitor, slpi (nvslpi), and evaluated their spatial and temporal expression during limb regeneration. nvelastasei is upregulated early in regeneration and is associated with sub ... | 2006 | 16508785 |
cardiovascular regeneration in non-mammalian model systems: what are the differences between newts and man? | the mammalian heart cannot regenerate substantial cardiac injuries, while certain non-mammalian vertebrates such as certain fish (danio rerio) and amphibiae (notophthalmus viridescens) are able to repair the heart without functional impairment. in mammalians, the prevailing repair process is accompanied by fibrosis and scarring, while zebrafish and newts can replace lost contractile tissue by newly formed cardiac muscle with only little or no scar formation. a better understanding of cardiac reg ... | 2007 | 17721612 |
widespread infection of the eastern red-spotted newt (notophthalmus viridescens) by a new species of amphibiocystidium, a genus of fungus-like mesomycetozoan parasites not previously reported in north america. | given the worldwide decline of amphibian populations due to emerging infectious diseases, it is imperative that we identify and address the causative agents. many of the pathogens recently implicated in amphibian mortality and morbidity have been fungal or members of a poorly understood group of fungus-like protists, the mesomycetozoans. one mesomycetozoan, amphibiocystidium ranae, is known to infect several european amphibian species and was associated with a recent decline of frogs in italy. h ... | 2008 | 17931460 |
frog virus 3-like infections in aquatic amphibian communities. | frog virus 3 (fv3) and fv3-like viruses, are members of the genus ranavirus (family iridoviridae), and they have been associated with infectious diseases that may be contributing to amphibian population declines. we examined the mode of transmission of an fv3-like virus, and potential hosts and reservoirs of the virus in a local amphibian community. using the polymerase chain reaction to detect infected animals, we found an fv3-like virus in south-central ontario, canada, amphibian communities, ... | 2008 | 18263826 |
widespread occurrence of the amphibian chytrid fungus batrachochytrium dendrobatidis in the southeastern usa. | from 1999 to 2006, we sampled > 1200 amphibians for the fungal pathogen batrachochytrium dendrobatidis (bd) at 30 sites in the southeastern usa. using histological techniques or pcr assays, we detected chytrid infection in 10 species of aquatic-breeding amphibians in 6 states. the prevalence of chytrid infection was 17.8% for samples of postmetamorphic amphibians examined using skin swab-pcr assays (n = 202 samples from 12 species at 4 sites). in this subset of samples, anurans had a much higher ... | 2008 | 19062748 |
preliminary amphibian health survey in the delaware water gap national recreation area. | to detect aquatic animal diseases of national concern, 111 individual amphibians, including wood frogs rana sylvatica (28), spring peepers pseudacris crucifer (35), red-spotted newts notophthalmus viridescens (41), and gray tree frogs hyla versicolor (7), were sampled at seven different sites in the delaware water gap national recreation area (dgnra), pennsylvania, from june 14 to july 19, 2007. these samples were screened for batrachochytrium dendrobatidis and viral pathogens at the u.s. fish a ... | 2010 | 20848885 |
what drives chytrid infections in newt populations? associations with substrate, temperature, and shade. | the pathogenic chytrid fungus batrachochytrium dendrobatidis (bd) is considered responsible for the population declines and extinctions of hundreds of amphibian species worldwide. the panzootic was likely triggered by human-assisted spread, but once the pathogen becomes established in a given region, its distribution is probably determined by local drivers. to assess the relative importance of potential drivers of infection in red-spotted newts (notophthalmus viridescens), we measured bd levels ... | 2010 | 21125308 |
differential rna-binding activity of the hnrnp g protein correlated with the sex genotype in the amphibian oocyte. | a proteomic approach has enabled the identification of an orthologue of the splicing factor hnrnp g in the amphibians xenopus tropicalis, ambystoma mexicanum, notophthalmus viridescens and pleurodeles walt, which shows a specific rna-binding affinity similar to that of the human hnrn g protein. three isoforms of this protein with a differential binding affinity for a specific rna probe were identified in the p. walt oocyte. in situ hybridization to lampbrush chromosomes of p. waltl revealed the ... | 2011 | 21278421 |
chemical defense of the eastern newt (notophthalmus viridescens): variation in efficiency against different consumers and in different habitats. | amphibian secondary metabolites are well known chemically, but their ecological functions are poorly understood--even for well-studied species. for example, the eastern newt (notophthalmus viridescens) is a well known secretor of tetrodotoxin (ttx), with this compound hypothesized to facilitate this salamander's coexistence with a variety of aquatic consumers across the eastern united states. however, this assumption of chemical defense is primarily based on observational data with low replicati ... | 2011 | 22164212 |
induction of human lampbrush chromosomes. | we previously demonstrated that sperm heads from amphibians (xenopus and rana) and zebrafish (danio) could form giant lampbrush chromosomes when injected into the nucleus of amphibian oocytes. however, similar experiments with mammalian sperm heads were unsuccessful. here, we describe a slightly modified procedure and demonstrate that human sperm heads can form giant lampbrush chromosomes when injected into the oocyte nucleus of the frog xenopus laevis or the newt notophthalmus viridescens. huma ... | 2012 | 23296495 |
a cytochemical study of myeloid bodies in the retinal pigment epithelium of the newt notophthalmus viridescens. | it has been suggested (yorke and dickson 1984) that myeloid bodies (mbs) in the retinal pigment epithelium (rpe) of the newt, notophthalmus viridescens, may represent areas of endoplasmic reticulum where lipids, such as 11-cis retinal derived from phagocytized outer segment tips, accumulate prior to esterification. experiments in which an artificial ester substrate was added during in-vitro incubations have shown that esterase activity is represented in all areas of the newt rpe endoplasmic reti ... | 2008 | 2577934 |
skin allografts in the newt, notopthalmus viridescens: cessation of blood flow as an indicator of rejection. | | 2015 | 4560032 |
regulation of motility in sperm of the red-spotted newt. | the motility of sperm was examined in vivo in the vas deferens, the spermatophore, and the spermatheca of the red-spotted newt and in in vitro preparations with variations in osmolality, hydrogen ion concentration, and concentrations of specific osmolytes. sperm were motile within the spermatophore, but little or no evidence of motility was seen in the spermatheca or the vas deferens. approximately 25% of sperm from the vas deferens became motile when dispersed in spermatic fluid plasma, the spe ... | 2013 | 3794627 |
a light and electron microscopic study of the respiratory epithelium of the adult aquatic newt, notophthalmus viridescens. | | 1990 | 1131745 |
an analysis of urodelian retinal regeneration. 3. degradation of extruded malanin granules in notophthalmus viridescens. | | 2015 | 4704217 |
an analysis of urodelian retinal regeneration. i. studies of the cellular source of retinal regeneration in notophthalmus viridescens utilizing 3 h-thymidine and colchicine. | | 2015 | 4704216 |
prolactin-induced modification on visual pigments in the eastern red-spotted newt, notophthalmus viridescens. | | 1992 | 1132673 |
a monoclonal antibody stains myogenic cells in regenerating newt muscle. | monoclonal antibodies have been used to study minced muscle regeneration in the adult newt, notophthalmus viridescens. the contralateral limb was amputated and the immunostaining patterns in the regenerating blastema were compared with the minced tissue in sectioned material. staining with a myofibre-specific antibody, called 12/101 (kintner & brockes, 1984), showed that myofibre degeneration was complete by 8-10 days after mincing, with myogenesis commencing 2 days later. another monoclonal ant ... | 2012 | 3446476 |
transcriptome analysis of newt lens regeneration reveals distinct gradients in gene expression patterns. | regeneration of the lens in newts is quite a unique process. the lens is removed in its entirety and regeneration ensues from the pigment epithelial cells of the dorsal iris via transdifferentiation. the same type of cells from the ventral iris are not capable of regenerating a lens. it is, thus, expected that differences between dorsal and ventral iris during the process of regeneration might provide important clues pertaining to the mechanism of regeneration. in this paper, we employed next ge ... | 2013 | 23613853 |
analysis of newly established est databases reveals similarities between heart regeneration in newt and fish. | the newt notophthalmus viridescens possesses the remarkable ability to respond to cardiac damage by formation of new myocardial tissue. surprisingly little is known about changes in gene activities that occur during the course of regeneration. to begin to decipher the molecular processes, that underlie restoration of functional cardiac tissue, we generated an est database from regenerating newt hearts and compared the transcriptional profile of selected candidates with genes deregulated during z ... | 2010 | 20047682 |
disease dynamics of red-spotted newts and their anuran prey in a montane pond community. | long-term monitoring of amphibians is needed to clarify population-level effects of ranaviruses (rv) and the fungal pathogen batrachochytrium dendrobatidis (bd). we investigated disease dynamics of co-occurring amphibian species and potential demographic consequences of rv and bd infections at a montane site in the southern appalachians, georgia, usa. our 3-yr study was unique in combining disease surveillance with intensive population monitoring at a site where both pathogens are present. we de ... | 2016 | 26912042 |
most of the dominant members of amphibian skin bacterial communities can be readily cultured. | currently, it is estimated that only 0.001% to 15% of bacteria in any given system can be cultured by use of commonly used techniques and media, yet culturing is critically important for investigations of bacterial function. despite this situation, few studies have attempted to link culture-dependent and culture-independent data for a single system to better understand which members of the microbial community are readily cultured. in amphibians, some cutaneous bacterial symbionts can inhibit est ... | 2015 | 26162880 |
temperature variability and moisture synergistically interact to exacerbate an epizootic disease. | climate change is altering global patterns of precipitation and temperature variability, with implications for parasitic diseases of humans and wildlife. a recent study confirmed predictions that increased temperature variability could exacerbate disease, because of lags in host acclimation following temperature shifts. however, the generality of these host acclimation effects and the potential for them to interact with other factors have yet to be tested. here, we report similar effects of host ... | 2015 | 25567647 |
batrachochytrium dendrobatidis infection dynamics vary seasonally in upstate new york, usa. | the amphibian disease chytridiomycosis, caused by the fungus batrachochytrium dendrobatidis (bd), is a major cause of worldwide amphibian declines and extinctions. although several studies indicate that bd prevalence and infection intensity vary seasonally, temporal variation of bd at high-latitude sites, such as the northeastern usa, is still poorly characterized. we screened amphibians for bd monthly at 2 study sites in new york state from april to october 2011 and used quantitative polymerase ... | 2014 | 25144117 |
amphibian skin may select for rare environmental microbes. | host-microbe symbioses rely on the successful transmission or acquisition of symbionts in each new generation. amphibians host a diverse cutaneous microbiota, and many of these symbionts appear to be mutualistic and may limit infection by the chytrid fungus, batrachochytrium dendrobatidis, which has caused global amphibian population declines and extinctions in recent decades. using bar-coded 454 pyrosequencing of the 16s rrna gene, we addressed the question of symbiont transmission by examining ... | 2014 | 24858782 |
limitations in response capacity of the newt, notophthalmus viridescens, to soluble and particulate antigens. | we have investigated the cellular basis of the failure of primitive extant vertebrates, e.g. notophthalmus viridescens, the american common newt, to respond to soluble thymus-dependent (td) antigens, e.g. keyhole limpet hemocyanin (klh). we have found that klh can be used to prime for amplification of a response to hapten, 2,4,6-trinitrophenyl (tnp) when it is conjugated to klh, only if both the unconjugated and conjugated klh are adsorbed onto bentonite particles. the response is monitored in t ... | 1982 | 6182036 |
bottom-up meets top-down: leaf litter inputs influence predator-prey interactions in wetlands. | while the common conceptual role of resource subsidies is one of bottom-up nutrient and energy supply, inputs can also alter the structural complexity of environments. this can further impact resource flow by providing refuge for prey and decreasing predation rates. however, the direct influence of different organic subsidies on predator-prey dynamics is rarely examined. in forested wetlands, leaf litter inputs are a dominant energy and nutrient resource and they can also increase benthic surfac ... | 2013 | 23386045 |
a new species of eimeria (apicomplexa: eimeriidae) from the marbled salamander, ambystoma opacum (caudata: ambystomatidae), from northern louisiana. | between december 2002 and june 2004, 10 marbled salamanders, ambystoma opacum, were examined for coccidian parasites. salamanders were collected in bradley (n = 2), little river (n = 1), miller (n = 1), and sevier (n = 1) counties, arkansas; webster parish, louisiana (n = 2); and bowie (n = 1) and nacogdoches (n = 2) counties, texas. two of 10 (20%) a. opacum from louisiana harbored an undescribed species of eimeria. oocysts of eimeria trauthi n. sp. were ellipsoidal, 36.6 x 33.1 (33-40 x 29-37) ... | 2008 | 18605797 |
predator size and phenology shape prey survival in temporary ponds. | theoretical efforts suggest that the relative sizes of predators and their prey can shape community dynamics, the structure of food webs, and the evolution of life histories. however, much of this work has assumed static predator and prey body sizes. the timing of recruitment and the growth patterns of both predator and prey have the potential to modify the strength of predator-prey interactions. in this study, i examined how predator size dynamics in 40 temporary ponds over a 3-year period affe ... | 2007 | 17891545 |
solution structure and phylogenetics of prod1, a member of the three-finger protein superfamily implicated in salamander limb regeneration. | following the amputation of a limb, newts and salamanders have the capability to regenerate the lost tissues via a complex process that takes place at the site of injury. initially these cells undergo dedifferentiation to a state competent to regenerate the missing limb structures. crucially, dedifferentiated cells have memory of their level of origin along the proximodistal (pd) axis of the limb, a property known as positional identity. notophthalmus viridescens prod1 is a cell-surface molecule ... | 2009 | 19771161 |
pigment patterns of larval salamanders (ambystomatidae, salamandridae): the role of the lateral line sensory system and the evolution of pattern-forming mechanisms. | in many species of salamanders, pigment cells derived from the neural crest give rise to a horizontal stripe pattern in hatchling larvae. a defining element of these horizontal stripe patterns is a region over the middle of the myotomes that is relatively free of melanophores. this study shows that formation of a "melanophore-free region" and horizontal stripe pattern in ambystoma tigrinum tigrinum (family ambystomatidae) correlates with the development of the trunk lateral line sensory system. ... | 1996 | 8626032 |
renal responses to mesotocin in adult ambystoma tigrinum and notophthalmus viridescens. | renal clearance methods were used to observe responses to the posterior pituitary peptide, mesotocin, by the kidneys of adult ambystoma tigrinum and notophthalmus viridescens. ambystoma tigrinum responded to hypophysectomy with a decrease in urine flow and glomerular filtration rate (gfr); however tubular water reabsorption was not affected. treatment with 5 ng/g mesotocin returned both urine flow and gfr to control levels. notophthalmus viridescens responded to mesotocin treatment with an incre ... | 1990 | 2365030 |
collagens from the skin and cartilage of the larval salamander ambystoma tigrinum. | the major collagens of larval salamander (ambystoma tigrinum) skin and cartilage were purified and characterized by cm-cellulose chromatography and amino acid analysis of the component alpha chains. the collagens are similar to type i (skin) and type ii (cartilage) collagens of birds and mammals. the type i molecule has the chain composition (alpha 1)2 alpha 2, and the type ii molecule is an (alpha 1)3 molecule. both collagens have lower levels of proline hydroxylation than the collagens isolate ... | 1982 | 7077269 |
reduction of sodium dependent stump currents disturbs urodele limb regeneration. | we have asked the question whether the natural electric currents which leave urodele limb stumps are in any way needed for their regeneration. as an initial test, we have greatly reduced such currents in the tiger salamander, ambystoma tigrinum, by applying 0.5 mm amiloride to the stump skin or by immersion of the animals in sodium depleted media. we have also reduced such currents in the red spotted newt, notophthalmus viridescens, by such immersion. limb regeneration in half of the amiloride-t ... | 1979 | 490133 |
an electron microscope study of the salamander thyroid during hormonal stimulation. | cytological changes in thyroid glands following administration of thyroid-stimulating hormone (tsh), were studied in adult salamanders, ambystoma tigrinum, triturus torosus, and triturus viridescens by electron and light microscopy. thyroids from untreated salamanders contained large follicles, faintly basophilic colloid, low follicle cells with flattened nuclei, and scant, slightly basophilic cytoplasm. after tsh administration the cell height and nuclear volume increased. cytoplasmic basophili ... | 1960 | 13852243 |
electroencephalographic studies, induced seizures, and their modification by phenobarbital, dilantin, and phenurone, in the salamanders, triturus viridescens and ambystoma tigrinum. | | 1954 | 13161848 |