Beyond equilibrium climate sensitivity

ISSN:1752-0908ISSN:1752-089

Isolation and characterization of lytic phages fromBacterioides ruminicola ssbrevis

Two bacteriophages (phgrBrb01 and phgrBrb02), lytic toBacteroides ruminicola ssbrevis AR20, were isolated from sewage water. Both phages possessed polyhedral heads and long noncontractile tails, and were classified as Siphoviridae of morphotype B1. Bacteria resistant to phages phgrBrb01 and phgrBrb02 arose following lysis of broth cultures. Survivors of phgrBrb01 infection were capsulated but remained susceptible to phgrBrb02 infection. Survivors of phgrBrb02 infection were noncapsulated and were resistant to attack by both phgrBrb01 and phgrBrb02. Neither phage lysogenized the host. Both phages contained double-stranded DNA, and their restriction endonuclease digestion patterns indicated that the phage genomes were circularly permuted and terminally redundant. Phage phgrBrb01 genome was examined in greater detail and confirmed to be circularly permuted, of size 33 kb, with a terminal redundancy of 2 kb, or 6% of the length of the genome. Circularly permuted genomes in phages of rumen bacteria do not appear to have been reported previously. At present, there is considerable interest in the genetic manipulation of rumen bacteria. The characterization of the phages described herein provides the basic information required for their use in the construction of vectors for the transfer of genetic material

Species limits and biogeography of Rhynchospiza sparrows

The genus Rhynchospiza comprises two species, the monotypic Tumbes Sparrow (R. stolzmanni) and the Stripe-crowned Sparrow (R. strigiceps) with subspecies strigiceps and dabbenei. In the study reported here we evaluated the taxonomic status of these taxa and discussed key features involved in speciation. All three taxa exhibited multiple differences in plumage, morphology, and vocalizations, supporting the recognition of three species in Rhynchospiza. The very large-billed R. stolzmanni has a song composed of a succession of faster complex trilled phrases, shows a small black loral line and dark-chestnut head stripes with large dark central-stripe to individual feathers, and is resident in the Tumbes region. The large and heavy dabbenei has a song consisting of a series of simple chirping notes, shows a large black loral crescent and chestnut head stripes with a reduced to absent dark center to feathers, and inhabits the Austral Yungas as a year-round resident. The small and pale strigiceps has a song consisting of a succession of complex trilled phrases, shows a small black loral line and rufous-brown head stripes with large dark central-stripe to feathers, and inhabits Dry and Sierran Chaco where it is a partial migrant. Locality data and ecological niche modeling show that dabbenei and strigiceps are allo-parapatric and use different altitudinally segregated habitats at their zone of parapatry. Molecular phylogenetic analyses (NADH dehydrogenase 2 [ND2] gene) revealed R. stolzmanni to be sister (11.5% divergent) to a recently diverged dabbenei and strigiceps clade (1.6% divergent). We conclude that the genus Rhynchospiza comprises three species-level entities, each restricted to a major biogeographic region, and that vocalizations and facial patterns provide key evidence on species limits in these otherwise similarly plumaged taxa. The evolutionary–cultural differences in songs, with complex phrases in those of R. strigiceps and R. stolzmanni, and single notes in the songs of R. dabbenei, suggest changes in the innate vocal learning template during speciation in the latter.Fil: Areta, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; ArgentinaFil: Depino, Emiliano Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; ArgentinaFil: Salvador, Sergio A.. No especifíca;Fil: Cardiff, Steven W.. State University of Louisiana; Estados UnidosFil: Epperly, Kevin. University of Washington; Estados UnidosFil: Holzmann, Ingrid. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; Argentin