Helminth parasites of northern spotted owls (Strix occidentalis caurina) from Oregon

Helminth parasites are reported for the first time from northern spotted owls. Seventy-one percent of a sample of Strix occidentalis caurina from western Oregon was infected. Nematodes (Porrocaecum depressum, Capillaria falconis, Microtetrameres sp. and Synhimantus hamatus) were the most prevalent parasites although cestodes (Paruterina rauschi) and acanthocephalans (Centrorhynchus conspectus) were also represented. There was an association between components of this helminth fauna and the diet of spotted owls which is dominated by small rodents. The occurrence of P. rauschi rather than P. candelabraria in this geographic region and host-species may provide additional support for recognition of a parapatric distribution in the ranges of Paruterina spp. among strigiforms in the Nearctic.     

Organic acid exudation and pH changes by Gordonia sp. and Pseudomonas fluorescens grown with P adsorbed to goethite

The actinomycete Gordonia sp. and the bacterium Pseudomonas fluorescens Pf-5 were grown in liquid media (pH 6.5) with phosphate adsorbed to the Fe-oxide/hydroxide goethite (Goe-P) and with soluble phosphate (0.1 mM or 1.0 mM P as KH2PO4). The two isolates showed distinct differences in their physiology. The pH of the medium was increased by Gordonia sp. by 1.1-1.7 units while it was decreased by P. fluorescens by 1.4-2.4 units. In all treatments the concentration of organic acids in the media with Gordonia sp. was up to 10 times lower (0.4-10.9 micromol L(-1)) than in media with P. fluorescens (33.4-84.4 micromol L(-1)). Gordonia sp. produced five different organic acids in varying amounts depending on P source and time. In contrast, P. fluorescens exuded mainly citrate and only small amounts of two to three other organic acids irrespective of P source or time.     

Mechanosensitivity of human osteosarcoma cells and phospholipase C beta2 expression

Bone adapts to mechanical load by osteosynthesis, suggesting that osteoblasts might respond to mechanical stimuli. We therefore investigated cell proliferation and phospholipase C (PLC) expression in osteoblasts. One Hertz uniaxial stretching at 4000 microstrains significantly increased the proliferation rates of human osteoblast-like osteosarcoma cell line MG-63 and primary human osteoblasts. However, U-2/OS, SaOS-2, OST, and MNNG/HOS cells showed no significant changes in proliferation rate. We investigated the expression pattern of different isoforms of PLC in these cell lines. We were able to detect PLC beta1, beta3, gamma1, gamma2, and delta1 in all cells, but PLC beta2 was only detectable in the mechanosensitive cells. We therefore investigated the possible role of PLC beta2 in mechanotransduction. Inducible antisense expression for 24h inhibited the translation of PLC beta1 in U-2/OS cells by 35% and PLC beta2 in MG-63 by 29%. Fluid shear flow experiments with MG-63 lacking PLC beta2 revealed a significantly higher level of cells losing attachment to coverslips and a significantly lower number of cells increasing intracellular free calcium.     

Coevolution and biogeography among Nematodirinae (Nematoda: Trichostrongylina) Lagomorpha and Artiodactyla (Mammalia): exploring determinants of history and structure for the northern fauna across the holarctic

Nematodes of the subfamily Nematodirinae are characteristic components of a Holarctic fauna. The topology of a generic-level phylogenetic hypothesis, patterns of diversity, and geographic distributions for respective nematode taxa in conjunction with data for host occurrence are consistent with primary distributions determined across Beringia for species of Murielus, Rauschia, Nematodirus, and Nematodirella. Ancestral hosts are represented by Lagomorpha, with evidence for a minimum of 1 host-switching-event and subsequent radiation in the Artiodactyla. Diversification may reflect vicariance of respective faunas along with episodic or cyclical range expansion and isolation across Beringia during the late Tertiary and Quaternary. Secondarily, species of Nematodirus attained a distribution in the Neotropical region with minimal diversification of an endemic fauna represented by Nematodirus molini among tayassuids, Nematodirus lamae among camelids and Nematodirus urichi in cervids during the Pleistocene. Nematodirines are a core component of an Arctic-Boreal fauna of zooparasitic nematodes (defined by latitude and altitude) adapted to transmission in extreme environments characterized by seasonally low temperatures and varying degrees of desiccation. The history and distribution of this fauna is examined in the context of biotic and abiotic determinants for geographic colonization and host switching with an exploration of predicted responses of complex host-parasite systems to ecological perturbation under a regime of global climate change.     

Eulimdana rauschorum n. sp., a filarioid nematode (Lemdaninae) from Larus dominicanus in Antarctica, with comments on evolution and biogeography

Eulimdana rauschorum n. sp. is described from southern black-backed gulls, Larus dominicanus Lichtenstein in Antarctica. The species is most similar to Eulimdana lari (Yamaguti, 1935) from Charadriiformes in the Holarctic. Males have spicules equal in length that are asymmetric in structure distally. There are 4-5 and 3-5 caudal papillae in rows to the right and left of the anus, and 2 small genital papillae at the posterolateral margin of the anus. Females have a variable number of prominent caudal papillae and large microfilariae (365 micron in length). The morphological similarities and host distribution of E. rauschorum and E. lari suggest they are sister taxa in which cladogenesis of the former accompanied the isolation and subsequent speciation of Larus dominicanus in the Southern Hemisphere.     

Parelaphostrongylus odocoilei in Columbian black-tailed deer from Oregon

Documenting the occurrence of Parelaphostrongylus odocoilei has historically relied on the morphological examination of adult worms collected from the skeletal muscle of definitive hosts, including deer. Recent advances in the knowledge of protostrongylid genetic sequences now permit larvae to be identified. Dorsal-spined larvae (DSLs) collected in 2003-2004 from the lung and feces of six Columbian black-tailed deer (Odocoileus hemionus columbianus) from Oregon were characterized genetically. The sequences from unknown DSLs were compared to those from morphologically validated adults and larvae of P. odocoilei at both the second internal transcribed spacer (ITS-2) of ribosomal DNA and the mitochondrial cytochrome oxidase II gene. We provide the first unequivocal identification of P. odocoilei in Columbian black-tailed deer from Oregon. The broader geographic distribution, prevalence, and pathology of P. odocoilei are not known in populations of Oregon deer.