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PubMed1986

Cytophotometric evidence of variation in genome size of desmognathine salamanders.

The amount of DNA per haploid genome, the C-value, is often directly correlated with nuclear and cell volume, but inversely correlated with cell replication rate. Also, rates of cellular growth sometimes appear to be correlated with organismal developmental rates and life history patterns. Among vertebrates, salamanders exhibit the greatest variation in genome size. In the present study we have examined interspecific and intraspecific variation in blood cell DNA levels in the genus Desmognathus, which shows greater variation in life history traits than any other salamander genus. Specimens of Desmognathus quadramaculatus, D. monticola, D. ochrophaeus and D. wrighti were collected from nature at two localities in the southern Appalachian Mountains. Estimates of genome size in pg of DNA were obtained from blood smears by DNA-Feulgen cytophotometry, using erythrocyte nuclei of Xenopus laevis as an internal reference standard of 6.35 pg DNA per cell. C-values of Desmognathus are the smallest in the order Caudata. Although significant variation in DNA levels was found among the four species, the differences were small, and do not support previously proposed relationships between C-value and life-history variation.

Animals↗
PubMed2003

The phylogenetics of Desmognathine salamander populations across the southern Appalachians.

Salamanders in the genus Desmognathus (Caudata: Plethodontidae) are distributed along an aquatic to terrestrial habitat gradient in the southern Appalachian Mountains. The spatial distribution of species is believed to have formed as aquatic ancestors displaced lineages by competition and predatory interactions into less optimal terrestrial habitats. Aquatic and terrestrial species may also display different patterns of genetic diversity due to the differing likelihood of gene flow via aquatic corridors. To determine whether phylogenetic patterns were consistent with these hypotheses, we sequenced portions of the cytochrome oxidase I and 12S rRNA genes of the mitochondrial genome from 96 individuals belonging to 10 species in the genus Desmognathus. In addition, we combined our dataset with an earlier published dataset for the 12S rRNA genes. The order of species divergence is consistent with aquatic ancestors having displaced taxa into more terrestrial habitats, but the major lineages within the genus Desmognathus arose suddenly, and therefore, the specific sequence of events is not well resolved. The phylogenetic analyses among species suggest that direct-development and a terrestrial lifestyle are ancestral in the genus Desmognathus, but the degree of adult terrestriallity is labile, with some species having re-invaded terrestrial habitats. We present evidence of a clade of Desmognathus quadramaculatus from North Carolina that is distinct from the D. quadramaculatus/Desmognathus marmoratus clade. Within species, estimates of Tajima's D and Fu and Li's statistics suggest the species experienced population expansions at different times in the past. Current levels of sequence diversity in northern populations, therefore, reflect different arrival times, and hence, differences in the opportunity for among population divergence. The recent arrival of most species over large portions of their geographic ranges suggests that most extant communities have been assembled, a posteriori, by the recent assortment of species along the aquatic to terrestrial gradient according to their ecologies.

Animals↗
PubMed2004

Molecular systematics and phylogeography of the Plethodon elongatus species group: combining phylogenetic and population genetic methods to investigate species history.

Plethodon elongatus and P. stormi (Caudata: Plethodontidae) are Pacific Northwest endemic species which occur in northwestern California and southwestern Oregon. Studies on these salamanders have resulted in differing taxonomic conclusions, but the underlying historical hypotheses, at both inter- and intraspecific levels, have never been examined in a molecular framework. Here, representatives of 81 populations from throughout the range of both taxa are sequenced. Portions of three mitochondrial protein-coding genes (cytochrome b, NADH dehydrogenase subunit 4, and ATPase 6) were sequenced. Four haplotype groups with nonoverlapping geographical ranges were recovered in separate and combined analyses of the data. One clade corresponds to the distribution of P. stormi, while the remaining three comprise P. elongatus. Phylogenetic relationships among haplotype groups differ in separate analyses of the genes but converge on a well-supported topology, with P. elongatus and P. stormi as monophyletic sister taxa, in combined Maximum Parsimony and Maximum Likelihood analyses. Population genetic analyses of mismatch distributions and Tajima's D-statistic are consistent with range expansion for the largest clade within P. elongatus, covering the northern two-thirds of the species range. In contrast, the P. stormi haplotype clade and the P. elongatus clade from the southern third of the species range may have been relatively stable. Morphological boundaries between P. elongatus and P. stormi are largely congruent with mitochondrial DNA breaks and continued treatment as sister taxa is supported. Although mitochondrial DNA haplotype groups may reflect historical separation within P. elongatus, genetic barriers are incongruent with intraspecific patterns of morphological variation.

Animals↗
PubMed2001

On the origin of and phylogenetic relationships among living amphibians.

The phylogenetic relationships among the three orders of modern amphibians (Caudata, Gymnophiona, and Anura) have been estimated based on both morphological and molecular evidence. Most morphological and paleontological studies of living and fossil amphibians support the hypothesis that salamanders and frogs are sister lineages (the Batrachia hypothesis) and that caecilians are more distantly related. Previous interpretations of molecular data based on nuclear and mitochondrial rRNA sequences suggested that salamanders and caecilians are sister groups to the exclusion of frogs. In an attempt to resolve this apparent conflict, the complete mitochondrial genomes of a salamander (Mertensiella luschani) and a caecilian (Typhlonectes natans) were determined (16,656 and 17,005 bp, respectively) and compared with previously published sequences from a frog (Xenopus laevis) and several other groups of vertebrates. Phylogenetic analyses of the mitochondrial data supported with high bootstrap values the monophyly of living amphibians with respect to other living groups of tetrapods, and a sister group relationship of salamanders and frogs. The lack of phylogenetically informative sites in the previous rRNA data sets (because of its shorter size and higher among-site rate variation) likely explains the discrepancy between our results and those based on previous molecular data. Strong support of the Batrachia hypothesis from both molecule- and morphology-based studies provides a robust phylogenetic framework that will be helpful to comparative studies among the three living orders of amphibians and will permit better understanding of the considerably divergent vertebral, brain, and digit developmental patterns found in frogs and salamanders.

Amphibians↗
PubMed1978

Sound transmission in the salamander ear.

The mode of stimulation of the ear by sounds is considered in Amphibia, in which it differs among the three Recent orders. Of special interest is the order Caudata, in which this stimulation takes a unique form: sounds applied to the oval window of one ear produce a path of vibratory motion that passes through the brain cavity to the oval window on the opposite side. In this course the vibratory movements traverse both right and left amphibian papillae, and both basilar papillae also in species that contain these endorgans. Thus, in the salamander the hearing is invariably binaural.

Animals↗
PubMed2005

Initial diversification of living amphibians predated the breakup of Pangaea.

The origin and divergence of the three living orders of amphibians (Anura, Caudata, Gymnophiona) and their main lineages are one of the most hotly debated topics in vertebrate evolution. Here, we present a robust molecular phylogeny based on the nuclear RAG1 gene as well as results from a variety of alternative independent molecular clock calibrations. Our analyses suggest that the origin and early divergence of the three living amphibian orders dates back to the Palaeozoic or early Mesozoic, before the breakup of Pangaea, and soon after the divergence from lobe-finned fishes. The resulting new biogeographic scenario, age estimate, and the inferred rapid divergence of the three lissamphibian orders may account for the lack of fossils that represent plausible ancestors or immediate sister taxa of all three orders and the heretofore paradoxical distribution of some amphibian fossil taxa. Furthermore, the ancient and rapid radiation of the three lissamphibian orders likely explains why branch lengths connecting their early nodes are particularly short, thus rendering phylogenetic inference of implicated relationships especially difficult.

Amphibians↗
PubMed1995

Phylogenetic relationships of amphibian families inferred from DNA sequences of mitochondrial 12S and 16S ribosomal RNA genes.

Nucleotide sequence comparisons were used to investigate ordinal and familial relationships within the class Amphibia. Approximately 850 base pairs of the mitochondrial 16S ribosomal RNA (rRNA) gene from representatives of 28 of the 40 families of extant amphibians were sequenced. Phylogenetic analyses of these data together with published data of the 12S rRNA gene for the same families and both genes for three more taxa (approximately 1,300 base pairs total for 35 taxa) support the monophyly of each of the three amphibian orders: Anura (confidence value with the interior-branch test: P(c) = 99%), Caudata (P(c) = 100%), and Gymnophiona (P(c) = 99%). An analysis using the four-cluster method cannot discriminate significantly between all three possible unrooted trees involving the three orders of amphibians and an outgroup. Within the Anura, there is support for the monophyly of the two suborders: Neobatrachia (P(c) = 100%) and Archaeobatrachia (P(c) = 97%); the latter was believed to be paraphyletic on the basis of morphology. Within the Archaeobatrachia, the following pairs of taxa cluster: Pelobatidae + Pelodytidae (P(c) = 99%), Pipidae + Rhinophrynidae (P(c) = 99%), Ascaphus + Leiopelmatidae (P(c) = 89%), and Bombina + Discoglossidae (P(c) = 99%). The latter six taxa cluster (P(c) = 94%) such that Pelobatidae + Pelodytidae forms a basal lineage within the Archaeobatrachia. Three major lineages are distinguished within the Neobatrachia: the superfamily Bufonoidea sensu Duellman (P(c) = 86%), the superfamily Ranoidea sensu Lynch (P(c) = 99%), and the Sooglossidae. Basal within the Bufonoidea, Myobatrachidae + Heleophrynidae cluster at P(c) = 96%. The enigmatic Dendrobatidae clusters with the bufonoid families (P(c) = 92%) and is excluded from the ranoid families (P(c) = 99%). (ABSTRACT TRUNCATED AT 250 WORDS)

Amphibians↗
PubMed1993

Morphological study of the teeth of Ambystoma maculatum, Salamandra salamandra and Aneides lugubris: fine structure and chemistry of enamel.

The functional teeth of adult salamander (Caudata): Ambystoma maculatum, Salamandra salamandra and Aneides lugubris were prepared for transmission electron microscopy and electron microprobe analysis of the elements and trace elements of the enamel layer. The arrangement of enamel crystals in these species is variable. The outer part of the enamel layer in which hydroxyapatite elements (Ca, P) and trace elements (e.g., F, Fe, Mg) are concentrated, is most mineralized. The concentration of trace elements are arrangement of crystals in the enamel layer differed in these species, may be related to the pattern of mineralization of enamel.

Ambystoma↗
PubMed1993

Spermathecal cytology of Ambystoma opacum (Amphibia: Ambystomatidae) and the phylogeny of sperm storage organs in female salamanders.

Sperm storage glands, spermathecae, were examined from mated female Ambystoma opacum during the breeding season. No differences occur in the spermathecal ultrastructure of individuals sacrificed prior to oviposition and those sacrificed within 3 days of removal from tended clutches of recently oviposited eggs. The simple tubuloalveolar glands produce two types of secretory vacuoles. Apical secretory vacuoles contain glycosaminoglycans for export into the lumen to bathe stored sperm, perhaps providing the chemical/osmotic environment necessary for sperm quiescence. The other type of secretory vacuole contains an unsaturated lipid that is produced for export into the connective tissue surrounding the spermathecae. The role of this secretion may involve the contraction of myoepithelial cells, resulting in sperm expulsion. Some sperm undergo degradation in the spermathecal epithelium, and an interepithelial leukocyte was observed in one specimen. Apical secretory vacuoles and sperm are absent from the spermathecae of a specimen sacrificed 62 days after removal from a tended egg clutch. This is the first report on the spermathecal cytology of a salamander from the Ambystomatidase, and comparisons with salamanders from other families provide a morphological basis for considering spermathecae polyphyletic within the Caudata.

Ambystoma↗
PubMed1980

Simultaneous fluorescent retrograde axonal tracing and immunofluorescent characterization of neurons.

A simple method is described for simultaneously double labeling single neurons with fluorescent retrograde axonal tracers and immunofluorescence using an antibody to serotonin. Caudata-putamen injection of orange fluorescent propidium iodide, in particular, proved effective in retrogradely labeling dorsal raphe cell bodies. These same perikarya could be stained green with the indirect immunofluorescent method, using green fluorescent fluorescein isothiocynate (FITC) as the second antibody.

Animals↗
PubMed1998

Amino acid sequence diversity of pancreatic polypeptide among the amphibia.

It has been suggested that the amino acid sequence of pancreatic polypeptide (PP) may provide a useful molecular marker with which to study evolutionary relationships between tetrapods but few PP sequences from amphibia are available to test this hypothesis. PPs have been purified from the pancreata of five species belonging to the different orders of amphibians. Their amino acid sequences were established as: APSEPEHPGD10 NASPDELAKY20 YSDLWQYITF30 VGRPRY for the lesser siren, Siren intermedia (Caudata); GPTEPIHPGK10 DATPEELTKY20 YSDLYDYITL30 VGRSRW for the caecilian, Typhlonectes natans (Gymnophiona); and TPSEPQHPGD10 QASPEQLAQY20 YSDLWQYITF30 VTRPRF for the cane toad, Bufo marinus (Anura). The structure of Rana sylvatica PP is the same as that of Rana catesbeiana PP whereas PP from the green frog Rana ridibunda contains one substitution (His6 --> Gln). The data provide further support for the conclusion that the amino acid sequence of PP has been poorly conserved during evolution with only 17 residues invariant among the eight species of amphibia yet studied and only 8 residues (Pro5, Pro8, Gly9, Ala12, Leu24, Tyr27, Arg33, and Arg35) invariant among all tetrapods. A maximum parsimony analysis based upon the amino acid sequence of PP and using the sequence of frog PYY as outgroup to polarize the in-group taxa generates a consensus phylogenetic tree in which the Amniota and Amphibia form two distinct clades. However, such a tree does not permit valid conclusions to be drawn regarding branching order within the Amphibia.

Amino Acid Sequence↗
PubMed2000

Islet hormones from the African bullfrog Pyxicephalus adspersus (Anura:Ranidae): structural characterization and phylogenetic implications.

The African bullfrog Pyxicephalus adspersus is generally classified along with frogs of the genus Rana in the subfamily Raninae of the family Ranidae but precise phylogenetic relationships between species are unclear. Pancreatic polypeptide (PP), insulin, and glucagon-like peptide (GLP-1) were isolated from an extract of P. adspersus pancreas and characterized structurally. A comparison of the amino acid sequence of Pyxicephalus PP (APSEPQHPGG(10)QATPEQLAQY(20)YSDLYQYITF(30)ITRPRF++ +. NH(2)) with those of the known amphibian PP molecules in a maximum parsimony analysis generates a single phylogenetic tree in which Pyxicephalus is the sister to the clade comprising the members of the genus Rana. The three orders of living amphibians form discrete clades with the representative of the Gymnophiona appearing as sister to the Caudata-Anura. In contrast, Pyxicephalus insulin (A chain, GIVEQCCHSA(10)CSLYDLENYC(20)N; B-chain, LANQHLCGSH(10)LVEALYMVCG(20)ERGFFYYPKS(30)) and and GLP-1 (HAEGTFTSDM(10)TSYLEEKAAK(20)EFVDWLIKGR(30)PK) resemble more closely the corresponding peptides from the cane toad Bufo marinus than the peptides from any species of Rana. Cladistic analysis based upon the amino acid sequences of insulin produced a polyphyletic assemblage with the Gymnophiona nesting within an unresolved clade containing the non-ranid frogs. The data support the assertion that the amino acid sequence of PP, but not those of the other islet hormones, is of value as a molecular marker for inferring phylogenetic relationships between early tetrapod species.

Amino Acid Sequence↗
PubMed1995

Structural comparison of cuticle and interstitial collagens from annelids living in shallow sea-water and at deep-sea hydrothermal vents.

Two types of annelid collagens of different sizes were purified, one from acetic acid extracts of the cuticle (length 2.5 microns) and the other, after pepsin digestion, from interstitial spaces of the body wall (0.3 micron). They were obtained from Alvinella pompejana, Alvinella caudata and Paralvinella grasslei collected at 2600 m depth around anoxic hydrothermal vents and from Arenicola marina and Nereis diversicolor living in shallow sea-water habitats. The length of the corresponding collagens from different species and their amino acid compositions including the hydroxylation of proline were remarkably similar. The melting point of the triple helix, however, differed between the Alvinella species (approximately 45 degrees C), Paralvinella (approximately 35 degrees C) and the shallow sea-water annelids (approximately 28 degrees C), indicating adaption to habitats with different temperatures. The cuticle collagens of the annelids possess a globular domain, which is apparently involved in oligomer formation, and show similar fragment pattern. Almost identical cross-striation patterns of segment-long-spacing segments of the interstitial collagens indicated sequence similarity, which was confirmed by partial Edman degradation of alpha-chains. These data showed almost complete identity between the two Alvinella species and a lower sequence identity with Paralvinella (approximately 95%), Arenicola (67 to 72%) and the vent vestimentiferan Riftia pachyptila (64 to 71%). The data suggest a close evolutionary relationship between these worms, despite a clear separation of habitat preference and thermal stability of the collagens.

Amino Acid Sequence↗
PubMed1996

A pollen allergen-encoding gene is expressed in wheat ovaries.

To isolate genes specifically expressed at the initiation of plant embryo development we have applied a sensitive subtractive hybridization technique for three isogenic wheat lines of the so-called 'Salmon system' with either zygotic or autonomous embryo development. Here we present a gene sequence showing a high homology to grass pollen allergens of type II/III thought to be expressed in pollen tissue only. Surprisingly, the pollen allergen-like sequence, designated Tri a III, is also expressed in gynoecia of the sexual, male fertile wheat line '(aestivum)-Salmon', whereas the two parthenogenetic and male sterile wheat lines '(caudata)-Salmon' and '(kotschyi)-Salmon' completely lack any Tri a III transcript. Our data suggest a positive correlation between the expression of this clone and the manifestation of male fertility. Northern and in situ hybridization analysis revealed that, in addition to its presence in pollen, Tri a III is expressed in the parenchymatous tissue of '(aestivum)-Salmon' ovaries exclusively at the day of anthesis. This precise temporal and spatial expression pattern suggests a more general function of the pollen allergen-like sequence Tri a III not limited to the exhibition of allergens in pollen grains.

Allergens↗
PubMed1986

Modification of the radioreceptor assay technique for estimation of serum neuroleptic drug levels leads to improved precision and sensitivity.

This report describes a series of modifications in the radioreceptor assay procedure for monitoring of serum neuroleptic levels which resulted in a substantial increase in precision and in a higher sensitivity than is the case with existing assays. The use of a dopamine receptor preparation from pig striatum yielded a lower limit of sensitivity for haloperidol of 0.08 ng/ml, when 0.5 ml serum was used in the assay; the intra- and inter-assay coefficients of variation were 3 and 9%, respectively. The relative antipsychotic potency of various neuroleptics correlated with their optimal daily dosage. Anticonvulsants (carbamazepine, phenytoin, barbiturates), anxiolytics (diazepam, bromazepam), as well as other drugs or hormones such as lithium, chloral hydrate, L-tryptophan or L-thyroxine did not interfere with the assay. Simultaneous determination of haloperidol by the radioreceptor assay and radioimmunoassay in serum showed good correlation (r = 0.994). Good correlation was also noted between the average optimal clinical daily dose of the neuroleptics and their affinity to the dopamine receptor of the porcine striatum (r = 0.891). Cross-laboratory assessment indicated good correlation between the estimation of haloperidol by a dopamine receptor preparation from bovine caudata and porcine striata (r = 0.830). The sensitivity of the present assay was improved about 30-fold compared to those previously reported.

Animals↗
PubMed1995

Organisation and sequence analysis of nuclear-encoded 5s ribosomal RNA genes in cryptomonad algae.

Southern hybridisation, polymerase chain reaction (PCR), and nucleotide sequence, data indicate that the 5s ribosomal RNA (rRNA) gene is linked to the main rRNA gene repeat in the nuclear genome of four cryptomonad algae (Rhinomonas pauca, Storeatula major, Komma caudata, and isolate Cs 134). The 5s gene is apparently transcribed in the same direction as the large and small subunit rRNA genes. The intergenic spacer between the 5s gene and the large subunit rRNA gene exhibits length and sequence polymorphism among the different species. Cryptomonads contain two different eukaryotic genomes: the host nucleus and the nucleus of a eukaryotic endosymbiont. Mapping experiments with isolated chromosomes of the host and endosymbiont genomes showed that the intergenic spacer between the large subunit and the 5s rRNA gene, which was amplified from total DNA by PCR, was derived from the host nuclear genome.

Base Sequence↗
PubMed1976

Histochemical studies on the distribution of alkaline phosphatase, acid phosphatase, 5-nucleotidase and ATPase in various reproductive tissues of certain digenetic trematodes.

Out of other functions performed by vitellaria in digenetic trematodes, their role in the formation of shell globules and shell membrane of the capsule, as well as in the excretion of iron with the help of vitamin C is very important. The present histochemical work shows the localization of certain enzymes in different parts of the reproductive system of ten species of trematodes viz.: Neopronocephalus triangularis Mehra, 1932; Glossimetra orientalis Mehra, 1937; Orientodiscus lobatus Srivastava, 1938; Eumegacetes artemii Mehra, 1935; Ganeo tigrinus mehra et Negi, 1928; Encyclometra caudata Dollfus, 1928; Thapariella udaipurensis Gupta and Sharma, 1970; Paradistomoides indicum Narain et Das, 1929; Patagifer wesleyi Verma, 1936; Proalarioides tropidonotus Vidyarthi, 1937 and indicates their functional significance. The hydrolytic enzymes (alkaline phosphatase, acid phosphatase, 5-nucleotidase and ATPase) are suggestive of their involvement in the uptake of certain nutrients, glycogen and lipoprotein being very significant among others. The four enzymes could also be detected in testes, ovary, uterus, cirrus sac and egg shell. The possible functional significance of each enzyme has been discussed.

Acid Phosphatase↗
PubMed2001

Neutrophil migration induced in vivo and in vitro by marine algal lectins.

OBJECTIVE AND DESIGN: Since some plant and mammalian lectins specific for monosaccharides are able to induce neutrophil migration, we studied the neutrophil migration-inducing activities of marine algal lectins, specific for complex oligosaccharides from glycoproteins, from Amansia multifida (AM), Bryothamnion seaforthii (BS), Bryothamnion triquetrum (BT) and Gracilaria caudata (GC). MATERIALS AND METHODS: The neutrophil migration-inducing activity of AM, BS, BT and GC was assayed in vitro and in vivo in the peritoneal cavity or dorsal air pouch of rats or mice, and was inhibited by glycans. RESULTS: AM, BS, BT and GC induced neutrophil migration in vivo and in vitro, determining bell-shaped dose-dependent curves. Maximal neutrophil influx was determined by BT in rats and by AM in mice. Maximal human neutrophil chemotaxis was obtained with GC. These activities were not inhibited by glycoproteins previously identified as being recognized by these lectins. D-mannose was a strong inhibitor, especially of BT activity both in vitro and in vivo. CONCLUSIONS: Algal lectins induced neutrophil migration, which was inhibited by a monosaccharide, contrasting with the view that they only recognize complex oligosaccharides. Neutrophil chemotaxis assays are appropriate to study low molecular mass lectins containing a single carbohydrate recognition domain, as is the case of some lectins from algae and mammals.

Animals↗