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Ben D Bell - One of the best experts on this subject based on the ideXlab platform.

  • how has the remnant population of the threatened frog leiopelma pakeka anura Leiopelmatidae fared on maud island new zealand over the past 25 years
    Austral Ecology, 2010
    Co-Authors: Ben D Bell, Shirley Pledger
    Abstract:

    Despite widespread global reports of declining amphibian populations, supporting long-term census data are few, limiting opportunities to study changes in numbers and survival over time. However, in New Zealand, for the past 25 years (1983–2008), we studied Leiopelma pakeka, a threatened, terrestrial frog that inhabits rocky boulder banks under forest on Maud Island. Using night sampling at least annually on two 12 × 12 m plots, we had 5390 captures of 1000+ individuals, 327 on one plot (grid 1), 751 on the other (grid 2). The mean (±SE) number of frogs found per night was 11.3 (±0.6) on grid 1 and 25.6 (±1.4) on grid 2. We used capture-recapture models to estimate population size, proportion of animals remaining beneath the surface and survival rate. The mean (±SE) population estimate was 131 (±14.7) frogs on grid 1 and 367 (±38.7) on grid 2. Over 25 years the estimated population increased on grid 1 and fluctuated on grid 2. Some frogs were captured on most sampling visits, others less often, evidently failing to emerge from cover each visit. Using a combination of open and closed population models, we estimated the mean (±SE) proportion remaining underground was 0.63 (±0.12) on grid 1 and 0.53 (±0.07) on grid 2. Our research represents one of the longest-run population studies of any frog, and we recorded significant longevity, two males reaching 35+ and 37+ years, a female 34+ years. No significant differences occurred between mean annual survival rates of apparent females and males, or between the two sites. The number of toes clipped for individual identification had little influence on the return rate, once the effect of time of first capture was removed.

  • the fate of a population of the endemic frog leiopelma pakeka anura Leiopelmatidae translocated to restored habitat on maud island new zealand
    New Zealand Journal of Zoology, 2004
    Co-Authors: Ben D Bell, Shirley Pledger, Paulette L Dewhurst
    Abstract:

    We assess the fate of 100 Leiopelma pakeka transferred in two batches from remnant forest on Maud Island to a new site at Boat Bay, 0.5 km away, in 1984–85. Seventy of the original 100 individual f...

  • leiopelma pakeka n sp anura Leiopelmatidae a cryptic species of frog from maud island new zealand and a reassessment of the conservation status of l hamiltoni from stephens island
    Journal of The Royal Society of New Zealand, 1998
    Co-Authors: Ben D Bell, Charles H Daugherty, Jennifer M Hay
    Abstract:

    Patterns of allozyme variation reveal that frogs from Maud Island, New Zealand, here designated Leiopelma pakeka, n sp , are specifically distinct from L hamiltoni from Stephens Island Previously, the two populations had been thought to be conspecific Leiopelma pakeka shows limited morphological differentiation from L hamiltoni, but is highly distinct genetically Among 12 allozyme loci resolved from toe tissue, the two taxa showed fixed differences at two loci and one significant frequency difference L hamiltoni was genetically more similar to L archeyi (Nei's D = 0 18) than to L pakeka (D = 0 24) The discovery that Maud Island and Stephens Island frogs are distinct species increases the conservation significance of both as the single known population of each species L hamiltoni is one of the world's rarest frogs and warrants the highest level of conservation protection

  • the taxonomic identity of a population of terrestrial leiopelma anura Leiopelmatidae recently discovered in the northern king country new zealand
    New Zealand Journal of Zoology, 1998
    Co-Authors: Ben D Bell, Charles H Daugherty, Rodney A Hitchmough
    Abstract:

    Abstract A terrestrial endemic frog resembling Leiopelma archeyi was discovered in the Whareorino Forest, northern King Country, New Zealand, in 1991, where it is broadly sympatric with L. hochstetteri. To clarify its taxonomic status, allozyme electrophoresis of toe tissue was used to compare it genetically with four other populations of terrestrial Leiopelma (L. archeyi from Tapu and Tokatea, Coromandel; L. hamiltoni from Stephens Island; L. pakeka from Maud Island). Thirteen presumed genetic (allozyme) loci could be consistently scored for the five populations. At 11 loci, no genetic differences were found between the Whareorino frog and the two Coromandel L. archeyi populations. Allelic frequencies differed slightly at two loci. We therefore conclude that the terrestrial Whareorino frog represents a western population of L. archeyi. L. hamiltoni from Stephens Island is genetically closer to L. archeyi than is L. pakeka from Maud Island. The Whareorino L. archeyi population is morphologically similar t...

  • habitat distribution and predation on a western population of terrestrial leiopelma anura Leiopelmatidae in the northern king country new zealand
    New Zealand Journal of Zoology, 1994
    Co-Authors: Tertia Thurley, Ben D Bell
    Abstract:

    Abstract A new population of terrestrial Leiopel‐matid frog was discovered in the Whareorino Forest, northern King Country, New Zealand, in 1991. Searches were carried out from June 1991 to December 1993 to determine the species present and to document variation in external morphology, habitat, and local distribution. These confirmed that a terrestrial frog resembling L. archeyi is present in the area, as well as Hochstetter's frog Leiopelma hochstetteri and the introduced Australian hylid frog Litoria aurea. In Whareorino Forest, the terrestrial Leiopelma was mostly above 500 m altitude and L. hochstetteri above 350 m. The terrestrial Leiopelma occupies sites under rocks and logs in forest. It also occurs in vegetation, such as crown fern Blechnum discolor, tree fern Cyathea smithii, hook grass Uncinia uncinata, and rice grass Microlaena avenacea. Egg clusters of this frog were found in crown fern and tree fern, as well as under stones. The terrestrial Leiopelma is susceptible to predation by Litoria aur...

Douglas C. Woodhams - One of the best experts on this subject based on the ideXlab platform.

  • the alyteserins two families of antimicrobial peptides from the skin secretions of the midwife toad alytes obstetricans alytidae
    Peptides, 2009
    Co-Authors: Michael J Conlon, Anni Demandt, Hubert Vaudry, Jérôme Leprince, Per F Nielsen, Douglas C. Woodhams
    Abstract:

    Abstract Two families of structurally related C-terminally α-amidated antimicrobial peptides have been identified in norepinephrine-stimulated skin secretions of the midwife toad Alytes obstetricans (Alytidae). The alyteserin-1 peptides (Gly-Leu-Lys-(Asp/Glu)-Ile-Phe-Lys-Ala-Gly-Leu-Gly-Ser-Leu-Val-Lys-(Gly/Asn)-Ile-Ala-Ala-His-Val-Ala-(Asn/Ser).NH 2 ) show limited structural similarity to the ascaphins from the skins of frogs of the family Leiopelmatidae. Alyteserin-2a (Ile-Leu-Gly-Lys-Leu-Leu-Ser-Thr-Ala-Ala-Gly-Leu-Leu-Ser-Asn-Leu.NH 2 ) and alyteserin-2b and -2c (Ile-Leu-Gly-Ala-Ile-Leu-Pro-Leu-Val-Ser-Gly-Leu-Leu-Ser-(Asn/Ser)-Lys-Leu.NH 2 ) show limited sequence identity with bombinin H6, present in the skins of frogs of the family Bombinatoridae. The alyteserin-1 peptides show selective growth inhibitory activity against the Gram-negative bacteria Escherichia coli (MIC = 25 μM) whereas alyteserin-2a is more potent against the Gram-positive bacteria Staphylococcus aureus (MIC = 50 μM). The hemolytic activity against human erythrocytes of all peptides tested is relatively weak (LC 50  > 100 μM). The data demonstrate that the frogs belonging to the family Alytidae are among those producing dermal antimicrobial peptides that may represent a component of the animal's system of innate immunity.

Michael J Conlon - One of the best experts on this subject based on the ideXlab platform.

  • the alyteserins two families of antimicrobial peptides from the skin secretions of the midwife toad alytes obstetricans alytidae
    Peptides, 2009
    Co-Authors: Michael J Conlon, Anni Demandt, Hubert Vaudry, Jérôme Leprince, Per F Nielsen, Douglas C. Woodhams
    Abstract:

    Abstract Two families of structurally related C-terminally α-amidated antimicrobial peptides have been identified in norepinephrine-stimulated skin secretions of the midwife toad Alytes obstetricans (Alytidae). The alyteserin-1 peptides (Gly-Leu-Lys-(Asp/Glu)-Ile-Phe-Lys-Ala-Gly-Leu-Gly-Ser-Leu-Val-Lys-(Gly/Asn)-Ile-Ala-Ala-His-Val-Ala-(Asn/Ser).NH 2 ) show limited structural similarity to the ascaphins from the skins of frogs of the family Leiopelmatidae. Alyteserin-2a (Ile-Leu-Gly-Lys-Leu-Leu-Ser-Thr-Ala-Ala-Gly-Leu-Leu-Ser-Asn-Leu.NH 2 ) and alyteserin-2b and -2c (Ile-Leu-Gly-Ala-Ile-Leu-Pro-Leu-Val-Ser-Gly-Leu-Leu-Ser-(Asn/Ser)-Lys-Leu.NH 2 ) show limited sequence identity with bombinin H6, present in the skins of frogs of the family Bombinatoridae. The alyteserin-1 peptides show selective growth inhibitory activity against the Gram-negative bacteria Escherichia coli (MIC = 25 μM) whereas alyteserin-2a is more potent against the Gram-positive bacteria Staphylococcus aureus (MIC = 50 μM). The hemolytic activity against human erythrocytes of all peptides tested is relatively weak (LC 50  > 100 μM). The data demonstrate that the frogs belonging to the family Alytidae are among those producing dermal antimicrobial peptides that may represent a component of the animal's system of innate immunity.

Norbert Nowotny - One of the best experts on this subject based on the ideXlab platform.

  • Antimicrobial Peptides From the Skins of North American Frogs
    Biochimica et biophysica acta, 2008
    Co-Authors: J. Michael Conlon, Jolanta Kolodziejek, Norbert Nowotny
    Abstract:

    Abstract North America is home to anuran species belonging to the families Bufonidae, Eleutherodactylidae, Hylidae, Leiopelmatidae, Ranidae, and Scaphiopodidae but antimicrobial peptides have been identified only in skin secretions and/or skin extracts of frogs belonging to the Leiopelmatidae (“tailed frogs”) and Ranidae (“true frogs”). Eight structurally-related cationic α-helical peptides with broad-spectrum antibacterial activity, termed ascaphins, have been isolated from specimens of Ascaphus truei (Leiopelmatidae) occupying a coastal range. Characterization of orthologous antimicrobial peptides from Ascaphus specimens occupying an inland range supports the proposal that this population should be regarded as a separate species A. montanus . Ascaphin-8 shows potential for development into a therapeutically valuable anti-infective agent. Peptides belonging to the brevinin-1, esculentin-1, esculentin-2, palustrin-1, palustrin-2, ranacyclin, ranatuerin-1, ranatuerin-2, and temporin families have been isolated from North American ranids. It is proposed that “ranalexins” represent brevinin-1 peptides that have undergone a four amino acid residue internal deletion. Current taxonomic recommendations divide North American frogs from the family Ranidae into two genera: Lithobates and Rana . Cladistic analysis based upon the amino acid sequences of the brevinin-1 peptides provides strong support for this assignment.

Anni Demandt - One of the best experts on this subject based on the ideXlab platform.

  • the alyteserins two families of antimicrobial peptides from the skin secretions of the midwife toad alytes obstetricans alytidae
    Peptides, 2009
    Co-Authors: Michael J Conlon, Anni Demandt, Hubert Vaudry, Jérôme Leprince, Per F Nielsen, Douglas C. Woodhams
    Abstract:

    Abstract Two families of structurally related C-terminally α-amidated antimicrobial peptides have been identified in norepinephrine-stimulated skin secretions of the midwife toad Alytes obstetricans (Alytidae). The alyteserin-1 peptides (Gly-Leu-Lys-(Asp/Glu)-Ile-Phe-Lys-Ala-Gly-Leu-Gly-Ser-Leu-Val-Lys-(Gly/Asn)-Ile-Ala-Ala-His-Val-Ala-(Asn/Ser).NH 2 ) show limited structural similarity to the ascaphins from the skins of frogs of the family Leiopelmatidae. Alyteserin-2a (Ile-Leu-Gly-Lys-Leu-Leu-Ser-Thr-Ala-Ala-Gly-Leu-Leu-Ser-Asn-Leu.NH 2 ) and alyteserin-2b and -2c (Ile-Leu-Gly-Ala-Ile-Leu-Pro-Leu-Val-Ser-Gly-Leu-Leu-Ser-(Asn/Ser)-Lys-Leu.NH 2 ) show limited sequence identity with bombinin H6, present in the skins of frogs of the family Bombinatoridae. The alyteserin-1 peptides show selective growth inhibitory activity against the Gram-negative bacteria Escherichia coli (MIC = 25 μM) whereas alyteserin-2a is more potent against the Gram-positive bacteria Staphylococcus aureus (MIC = 50 μM). The hemolytic activity against human erythrocytes of all peptides tested is relatively weak (LC 50  > 100 μM). The data demonstrate that the frogs belonging to the family Alytidae are among those producing dermal antimicrobial peptides that may represent a component of the animal's system of innate immunity.