Genetic population structure of the sagebrush Brewer’s sparrow, <Emphasis Type="Italic">Spizella breweri breweri</Emphasis>, in a fragmented landscape at the northern range periphery

Assessing the genetic consequences of habitat fragmentation is a crucial step in conservation planning for species in endangered habitats. We tested for the impact of natural habitat fragmentation on gene flow and genetic diversity in seven northern breeding locations of the sagebrush Brewer’s sparrow, Spizella breweri breweri. Genetic analyses using five highly variable DNA microsatellite loci suggested that individuals sampled within a sagebrush landscape fragmented by natural elements such as coniferous forest, comprise a single genetic population and that gene flow among them is unimpeded. We posit that juvenile dispersal links seemingly isolated breeding locales of this species, and discuss implications of our findings for conservation of migratory songbirds in the northern portion of their ranges in light of potential shifts in distribution due to climate change.     

Uptake and intra-inclusion accumulation of exogenous immunoglobulin by <Emphasis Type="Italic">Chlamydia</Emphasis>-infected cells

Background  

Obligate intracellular pathogens belonging to the Chlamydiaceae family possess a number of mechanisms by which to manipulate the host cell and surrounding environment. Such capabilities include the inhibition of apoptosis, down-regulation of major histocompatability complex (MHC) and CD1/d gene expression, and the acquisition of host-synthesized nutrients. It is also documented that a limited number of host-derived macromolecules such as β-catenin and sphingomyelin accumulate within the inclusion.