The Chinese bamboo leaf odorous frog (Rana (Odorrana) versabilis) and North American Rana frogs share the same families of skin antimicrobial peptides

The Chinese bamboo leaf odorous frog (Rana (Odorrana) versabilis) and the North American pickerel frog (Rana palustris) occupy different ecological niches on two different continents with no overlap in geographical distribution. R. palustris skin secretions contain a formidable array of antimicrobial peptides including homologs of brevinin-1, esculentin-1, esculentin-2, ranatuerin-2, a temporin and a family of peptides considered of unique structural attributes when isolated, palustrins 1-3. Here we describe the structures of mature peptides and precursors of eight putative antimicrobial peptides from the skin secretion of the Chinese bamboo leaf odorous frog (Rana (Odorrana) versabilis). Each peptide represents a structural homolog of respective peptide families isolated from R. palustris, including two peptides identical in primary structure to palustrin 1c and palustrin 3b. Additionally, two peptides were found to be structural homologs of ranatuerin 2B and ranatuerin 2P from the closely-related North American species, Rana berlandieri (the Rio Grande leopard frog) and Rana pipiens (the Northern leopard frog), respectively. Both palustrins and ranatuerins have hitherto been considered unique to North American ranid frogs. The use of primary structures of amphibian skin antimicrobial peptides is thus questionable as a taxonomic device or alternatively, the micro-evolution and/or ancestry of ranid frogs is more highly complex than previously thought.     

Species limits and phylogeography of North American cricket frogs (Acris: Hylidae)

Cricket frogs are widely distributed across the eastern United States and two species, the northern cricket frog (Acris crepitans) and the southern cricket frog (A. gryllus) are currently recognized. We generated a phylogenetic hypothesis for Acris using fragments of nuclear and mitochondrial genes in separate and combined phylogenetic analyses. We also used distance methods and fixation indices to evaluate species limits within the genus and the validity of currently recognized subspecies of A. crepitans. The distributions of existing A. crepitans subspecies, defined by morphology and call types, do not match the distributions of evolutionary lineages recovered using our genetic data. We discuss a scenario of call evolution to explain this disparity. We also recovered distinct phylogeographic groups within A. crepitans and A. gryllus that are congruent with other codistributed taxa. Under a lineage-based species concept, we recognize Acris blanchardi as a distinct species. The importance of this revised taxonomy is discussed in light of the dramatic declines in A. blanchardi across the northern and western portions of its range.     

Phylogenetic relationships of the North American chorus frogs (Pseudacris: Hylidae)

We examined phylogenetic relationships of the North American chorus frogs (Pseudacris: Hylidae) from 38 populations using 2.4 kb of 12S and 16S mtDNA to elucidate species relationships and examine congruence of previous phylogenetic hypotheses. Parsimony, maximum likelihood, and Bayesian phylogenies are consistent and reveal four strongly supported clades within Pseudacris: (1). A West Coast Clade containing regilla and cadaverina, (2). a Fat Frog Clade including ornata, streckeri, and illinoensis, (3). a Crucifer Clade consisting of crucifer and ocularis, and (4). a Trilling Frog Clade containing all other Pseudacris. Explicit hypothesis testing using parametric bootstrapping indicates that previous phylogenetic hypotheses are rejected by our sequence dataset. Within the Trilling Frog Clade, brimleyi and brachyphona form the sister group to the Nigrita Clade: nigrita, feriarum, triseriata, kalmi, clarkii, and maculata. The Nigrita Clade shows geographic division into three clades: (1). populations of maculata and triseriata west of the Mississippi River and Canadian populations, (2). southeastern US populations of feriarum and nigrita, and (3). northeastern US populations of feriarum, kalmi, and triseriata. We find that subspecific epithets for crucifer (crucifer and bartramiana) and nigrita (nigrita and verrucosa) are uninformative, therefore we discourage recognition of these subspecies. Pseudacris regilla, cadaverina, ocularis, and crucifer are maintained in Pseudacris.     

Antimicrobial peptides from ranid frogs: taxonomic and phylogenetic markers and a potential source of new therapeutic agents

Granular glands in the skins of frogs of the genus Rana, a widely distributed group with over 250 species, synthesize and secrete a remarkably diverse array of peptides with antimicrobial activity that are believed to have arisen as a result of multiple gene duplication events. Almost without exception, these components are hydrophobic, cationic and form an amphipathic alpha-helix in a membrane-mimetic solvent. The peptides can be grouped into families on the basis of structural similarity. To date, brevinin-1, esculentin-1, esculentin-2, and temporin peptides have been found in ranid frogs of both Eurasian and North American origin; ranalexin, ranatuerin-1, ranatuerin-2 and palustrin peptides only in N. American frogs; and brevinin-2, tigerinin, japonicin, nigrocin and melittin-related peptides only in Eurasian frogs. It is generally assumed that this structurally diversity serves to protect the organism against a wide range of pathogens but convincing evidence in support of this hypothesis is still required. The possibility that "antimicrobial peptides" fulfill additional or alternative biological functions should not be rejected. The molecular heterogeneity of the peptide families, particularly brevinin-1, brevinin-2 and ranatuerin-2, may be exploited for the purposes of unequivocal identification of specimens and for an understanding of phylogenetic interrelationships between species. The broad-spectrum antibacterial and antifungal activities of certain peptides, for example esculentin-1, ranalexin-1 and ranatuerin, together with their relatively low hemolytic activity, make them candidates for development into therapeutically useful anti-infective agents.     

Microsatellite population genetics of the emerald ash borer (Agrilus planipennis Fairmaire): comparisons between Asian and North American populations

The emerald ash borer (EAB) (Agrilus planipennis Fairmaire) (Coleoptera; Buprestidae), is an invasive wood-boring beetle native to northeast Asia. This species was first detected in Michigan USA in 2002, and is a significant threat to native and ornamental ash tree species (Fraxinus spp.) throughout North America. We characterized seven polymorphic microsatellite markers for EAB and used these to investigate EAB population structure in the early invasive populations within North America and in comparison with Asia. We found 2–9 alleles per microsatellite locus, no evidence of linkage disequilibrium, and no association with known coding sequences, suggesting that these markers are suitable for population genetic analysis. Microsatellite population genetic structure was examined in 48 EAB populations sampled between 2003 and 2008 from five regions, three in the introduced range, Michigan (US) and Ontario and Quebec (Canada) and two Asian regions, China and South Korea, where EAB is native. We found significant genetic variation geographically but not temporally in EAB populations. Bayesian clustering analyses of individual microsatellite genotypes showed strong clustering among multiple North American populations and populations in both China and South Korea. Finally, allelic richness and expected heterozygosity were higher in the native range of EAB, but there was no difference in observed heterozygosity, suggesting a significant loss of alleles upon introduction but no significant change in the distribution of alleles within and among individuals.     

Juvenile salmon in estuaries: comparisons between North American Atlantic and Pacific salmon populations

All anadromous fishes, including juvenile salmon, encounter estuarine habitats as they transition from riverine to marine environments. We compare the estuarine use between juvenile Atlantic salmon (Salmo salar) in the Penobscot River estuary and Pacific salmon (Oncorhynchus spp.) in the Columbia River estuary. Both estuaries have been degraded by anthropogenic activities. Atlantic and Pacific salmon populations in both basins rely heavily on hatchery inputs for persistence. Pacific salmon, as a group, represent a continuum of estuarine use, from species that move through rapidly to those that make extensive use of estuarine habitats. While Atlantic salmon estuarine use is predominantly similar to rapidly moving Pacific salmon, they can exhibit nearly the entire range of Pacific salmon estuarine use. Both slow and rapidly migrating Atlantic and Pacific salmon actively feed in estuarine environments, consuming insect and invertebrate prey. Interactions between juvenile salmon and estuarine fish communities are poorly understood in both estuaries, although they experience similar avian and marine mammal predators. Estuaries are clearly important for Atlantic and Pacific salmon, yet our understanding of this use is currently insufficient to make informed judgments about habitat quality or overall estuary health. This review of salmonid migration through and residency within estuaries identifies actions that could hasten restoration of both Atlantic and Pacific salmon populations.     

Taxonomical significance of the leaf indument inDryopteris (Pteridophyta): I. Some North American,Macaronesian and European taxa

The leaf indument of a number of North American, Macaronesian and EuropeanDryopteris taxa is described. Trichome characters provide very useful taxonomical data for the study of species complexes and for tracing relationships among geographically isolated or separated taxa. The new combination,D. expansa var.alpina, is made. The present study sustains best theWagner D. semicristata relationship scheme.     

ITS sequences from nuclear rDNA suggest unexpected phylogenetic relationships between Euro-Mediterranean, East Asiatic and North American taxa ofQuercus (Fagaceae)

Nucleotide sequences from the internal transcribed spacer (ITS) regions of the 18S–26S nuclear ribosomal DNA have been studied from ten species ofQuercus (representing four subgenera),Castanea sativa andFagus sylvatica, as a preliminary molecular contribution to the still poorly understood systematics and evolution ofFagaceae. The resulting matrix has been used to calculate pair-wise sequence divergence indices and to construct a maximum parsimony tree forQuercus coding indels as a fifth state. Divergence is greater forQuercus vs.Fagus than forQuercus vs.Castanea. The tree for theQuercus taxa studied reveals two clearly divergent clades. In clade I the evergreen W MediterraneanQ. suber appears in a basal position as sister to more distal deciduous taxa, i.e. the E MediterraneanQ. macrolepis and the E AsiaticQ. acutissima (all formerly united as different sections under the apparently polyphyletic subg.Cerris), andQ. rubra (a representative of the N American subg.Erythrobalanus), forming a pair withQ. acutissima. In clade II the evergreen southeastern N AmericanQ. virginiana is basal and sister to the remaining three branches, i.e. a pair of evergreen Mediterranean taxa withQ. ilex andQ. coccifera (subg.Sclerophyllodrys), the deciduous but otherwise plesiomorphic SE European/SW AsiaticQ. cerris (type species of subg.Cerris), and the related but more apomorphic European pairQ. petraea andQ. robur (subg.Quercus). These results partly conflict with current taxonomic classification but are supported by some anatomical and morphological characters. They document polyphyletic lines from evergreen to deciduous taxa and suggest Tertiary transcontinental connections within the genus.     

Identification and Functional Analysis of Novel Bradykinin-Related Peptides (BRPs) from Skin Secretions of Five Asian Frogs

In recent decades, various types of bioactive substances have been identified from amphibian skin and its secretions. Bradykinin-related peptides (BRPs) are among these compounds that make up the host defence system of amphibians. In the present study, we identified six novel BRPs, amolopkinin-GN1, amolopkinin-RK1, amolopkinin-TR1, amolopkinin-LF1, ranakinin-MS1, and ranakinin-MS2, from five East Asian amphibians, Amolops granulosus, Amolops ricketti, Amolops torrentis, Amolops lifanensis, and Hylarana maosonensis. This is the first report on BRPs in the skin of these species. Physiological assays reveal that these peptides have a contractive effect on the smooth muscle of rat ileum.     

Molecular genetics and speciation in Elliptio and its relationships to other taxa of North American Unionidae (Bivalvia)

The genetic relationships among 30 populations of 11 species and five genera of North American Unionidae were assessed by using standard allozyme procedures. Emphasis was on relationships among populations and species of Elliptio and Fusconaia. Multi-dimensional scaling based on a matrix of Nei's (1972) genetic distances substantiated the immunoelectrophoretic results of Davis&Fuller 1981, which demonstrated the distinct and divergent taxonomic groups Anodontinae, Margaritiferinae, and Ambleminae, plus die close relationship of Elliptio and Fusconaia , which justifies their inclusion within the same tribe. Genetic distance appears to increase regularly with time since divergence of taxa. The E. complanata species group is an apparently recent radiation and probably is actively radiating today. The I values among species of this group range from 0.90 to 0.99. Considerable heterozygosity, numerous polymorphic loci, and much interpopuladon phenotypic diversity was also recorded for this group. Some taxa mat have been considered synonyms are demonstrated to be valid species. Reasons for the low genetic distances among unionid taxa are discussed. Standard allozyme analyses are shown to be of great value for assessing relationships among unionid taxa.     

Interstitial hybridization sites of the (TTAGGG)n telomeric sequence on the chromosomes of some North American hylid frogs.

Interstitial hybridization sites for the (TTAGGG)n telomeric repeat sequence were present in all seven species of hylid frogs examined and in a triploid hybrid between two of the species. Intra- and interspecific differences and similarities in hybridization sites agreed with what is known about the systematics of these species. Chromosome fusions, fissions, and inversions do not appear to have played a role in the evolution of the interstitial sites for the telomeric repeat in the species examined.     

Assembly of the eastern North American herpetofauna: new evidence from lizards and frogs

Darwin first recognized the importance of episodic intercontinental dispersal in the establishment of worldwide biotic diversity. Faunal exchange across the Bering Land Bridge is a major example of such dispersal. Here, we demonstrate with mitochondrial DNA evidence that three independent dispersal events from Asia to North America are the source for almost all lizard taxa found in continental eastern North America. Two other dispersal events across Beringia account for observed diversity among North American ranid frogs, one of the most species-rich groups of frogs in eastern North America. The contribution of faunal elements from Asia via dispersal across Beringia is a dominant theme in the historical assembly of the eastern North American herpetofauna.     

Anatomical studies of Carex cuchumatanensis,C. decidua,and C. hermannh (Cyperaceae) and comparisons with north American taxa of the C. acuta complex

Foliar anatomy and micromorphology of perigynia and achenes were investigated for three taxa of theCarex acuta complex of sect.Phacocystis Dumort. in Middle and South America. Anatomical characters appear to be conservative, and show little variation amongC. cuchumatanensis Standl. & Steyerm.,C. decidua F. Boott, andC. hermannii Cochrane. Leaves of all species are amphistomatous, with stomates and papillae on both epidermal surfaces, and have a single layer of bulliform cells but differ in the number of vascular bundles. Perigynia have epidermal cells with thin, convex, outer walls that are collapsed in dired specimens, and epidermal cells of achenes each have a single, rounded, nodulose silica-body with a basal platform. Anatomical data are useful in resolving the affinities among these species, and show that they are anatomically indistinguishable fromC. lenticularis Michx. These four New World endemics differe substantially fromC. nigra (L.) Reichard.     

Hybridization between South American Jarilla and North American diploid creosotebush (Larrea,Zygophyllaceae)

Different strains of the two diploidLarrea speciesL. divaricata (S. America) andL. tridentata (N. America), are compared morphologically, cytologically, and in their seed proteins. There are minor differences, also in chiasma frequencies. Experimental F₁ hybrids have near-normal meiosis but are semisterile. The parental species, therefore, biologically may be considered allopatric semispecies.     

A phylogeny of ranid frogs (Anura: Ranoidea: Ranidae), based on a simultaneous analysis of morphological and molecular data

During the last two decades, major taxonomic rearrangements were instituted in the anuran family Ranidae. Most of these changes were not based on phylogenetic analysis, and many are controversial. Addressing the phylogeny of Ranidae requires broader taxon sampling within the superfamily Ranoidea, the phylogenetic relationships and higher classification of which are also in a state of flux. No comprehensive attempt has yet been made to reconstruct ranid phylogeny using both morphological and molecular data. In the present contribution, data from 178 organismal characters were collated for 74 exemplar species representing the families Arthroleptidae, Hemisotidae, Hyperoliidae, Mantellidae Microhylidae, Petropedetidae, Rhacophoridae, Sooglossidae, and most subfamilies of Ranidae. These were combined with ～1 kb of DNA sequence from the mitochondrial 12S rDNA and 16S rDNA gene regions in a simultaneous parsimony analysis with direct optimization. Results support the classification of Hemisus with the brevicipitine microhylids, confirm that Arthroleptidae (and its two component subfamilies Astylosterninae and Arthroleptinae) are monophyletic, and advocate the recognition of Leptopelidae. Monophyly of Ranidae is compromised by recognition of Petropedetidae, Rhacophoridae and Mantellidae, which should be recognized as subfamilies of Ranidae at present. Furthermore, Petropedetidae was found to be grossly paraphyletic, comprising three clades which are all considered separate subfamilies of Ranidae, i.e., Petropedetinae, Phrynobatrachinae and Cacosterninae. Three well defined subfamilies of Ranidae were consistently retrieved as monophyletic in a sensitivity analysis, i.e., Tomopterninae, Ptychadeninae and Pyxicephalinae. However, Ptychadeninae and Pyxicephalinae were embedded in Raninae and Dicroglossinae, respectively. Ceratobatrachinae is removed from Dicroglossinae. Dicroglossinae is synonymized with Pyxicephalinae. A new subfamily Strongylopinae is proposed. Raninae should be conservatively treated as a “metataxon” (sensu Ford and Cannatella, 1993 ) until such time as it is fully revised. Tomopterninae is removed from synonymy with Cacosterninae. Morphological synapomorphies are reported for major monophyletic clades retrieved in the simultaneous analysis with equal weights. The present study found that many Old World clades appear to contain both African and Asian taxa, contrary to the findings of some recent biogeographical analyses. This study demonstrates the value of broad taxonomic sampling in ranid phylogeny, and highlights the immense contribution that can be made from detailed morphological data. © The Willi Hennig Society 2005.     

New taxa of Kalyptorhynchia (Platyhelminthes) from the N. American Pacific coast

From the N. American Pacific coast the following new kalyptorhynchian taxa are described: Cicerinabicirrata, Cicerina triangularis, Placorhynchus pacificus, Uncinorhynchus pacificus, Proschizorhynchella lingulata, Proschizorhynchella inflata, Proschizorhynchella schilkei, Schizochilus hoxholdi, Paraschizorhynchoides glandulis Schilke subsp. hopkinsi, Cheliplana californica and Cheliplana elkhornica . The taxonomy of the species is discusscd and supplementary remarks arc made on some species from other areas.     

Discordant temporal and geographic patterns in maternal lineages of eastern North American frogs, Rana catesbeiana (Ranidae) and Pseudacris crucifer (Hylidae)

Whether the Pleistocene has had a disproportionate impact on the recent diversification of temperate species, or played a lesser role in a more protracted process, has been a prominent evolutionary debate for the past decade. We used cytochrome b sequences to reconstruct the evolutionary histories of two widely co-distributed, and ecologically divergent frogs (Rana catesbeiana and Pseudacris crucifer) to examine the role of the Pleistocene in structuring these species. Results for R. catesbeiana reflect a pattern of allopatric fragmentation, likely in Coastal Plain refugia on either side of the Mississippi River dating to the mid to early Pleistocene. In contrast, P. crucifer contains numerous divergent lineages, including one west of the Mississippi River in the Interior Highlands, and in the east, multiple lineages that likely expanded from a number of southern Appalachian refugia with lineage sundering originating in the late Pliocene. Large-scale phylogeographic comparisons between these and other eastern North American species reflect both congruent and independent patterns of diversification, possibly reflecting the relative importance of dispersal ability and habitat associations. Although intra-lineage diversification has been structured by repeated Pleistocene glaciations, lineage sundering likely dates at least to the Pliocene in most (but not all) northern temperate amphibian and reptile species studied to date.     

The chromosomes of Rhynchosciara baschanti (Diptera: Sciaridae): molecular cytogenetic comparisons with taxa in the americana-like group.

Polytene chromosome analysis is presented for Rhynchosciara baschanti, a species belonging to the americana-like group of Rhynchosciara. R. baschanti chromosomes show morphological differences in centromeric and telomeric regions compared to two other members within the group, R. americana and R. hollaenderi. In addition, fixed band and autosomal inversion differences were noted. Physical mapping data showed synteny among the taxa under study for DNA puffs and single-copy or histone gene probes, whereas rDNA and poly-(r)A probes showed different diagnostic patterns. The activity of developmentally active genes and the pattern of thymidine incorporation into DNA puff sites of R. baschanti are consistent with those found in the two previously studied species, except for lower levels of expression at some of these sites. These results suggest that differential duplication of specific DNA sequences, in particular repetitive and homopolymeric DNA, has played a role in the chromosomal evolution of these Rhynchosciara species. Inversions and band dimorphisms have also occurred, but the processes leading to their maintenance and fixation appear to have been slow, since these three species are in general chromosomally monomorphic.