Ambient temperature-mediated changes in hepatic gene expression of a mammalian herbivore (Neotoma lepida).

Herbivores regularly ingest natural toxins produced by plants as a defence against herbivory. Recent work suggests that compound toxicity is exacerbated at higher ambient temperatures. This phenomenon, known as temperature-dependent toxicity (TDT), is the likely result of decreased liver function at warmer temperatures; however, the underlying cause of TDT remains speculative.

Evidence for functional convergence in genes upregulated by herbivores ingesting plant secondary compounds.

Background: Nearly 40 years ago, Freeland and Janzen predicted that liver biotransformation enzymes dictated diet selection by herbivores. Despite decades of research on model species and humans, little is known about the biotransformation mechanisms used by mammalian herbivores to metabolize plant secondary compounds (PSCs). We investigated the independent evolution of PSC biotransformation mechanisms by capitalizing on a dramatic diet change event-the dietary inclusion of creosote bush (Larrea tridentata)-that occurred in the recent evolutionary history of two species of woodrats (Neotoma lepida and N.

Functional characterization of cytochromes P450 2B from the desert woodrat Neotoma lepida.

Mammalian detoxification processes have been the focus of intense research, but little is known about how wild herbivores process plant secondary compounds, many of which have medicinal value or are drugs. cDNA sequences that code for three enzymes of the cytochrome P450 (CYP) 2B subfamily, here termed 2B35, 2B36, and 2B37 have been recently identified from a wild rodent, the desert woodrat (Malenke et al., 2012).

Hepatic gene expression in herbivores on diets with natural and novel plant secondary compounds.

Herbivores are predicted to evolve appropriate mechanisms to process the plant secondary compounds (PSCs) in their diet, and these mechanisms are likely specific to particular suites of PSCs. Changes in diet composition over evolutionary time should select for appropriate alterations in metabolism of the more recent dietary components. We investigated differences in gene expression profiles in the liver with respect to prior ecological and evolutionary experience with PSCs in the desert woodrat, Neotoma lepida.

Cytochrome P450 2B diversity and dietary novelty in the herbivorous, desert woodrat (Neotoma lepida).

Detoxification enzymes play a key role in plant-herbivore interactions, contributing to the on-going evolution of ecosystem functional diversity. Mammalian detoxification systems have been well studied by the medical and pharmacological industries to understand human drug metabolism; however, little is known of the mechanisms employed by wild herbivores to metabolize toxic plant secondary compounds. Using a wild rodent herbivore, the desert woodrat (Neotoma lepida), we investigated genomic structural variation, sequence variability, and expression patterns in a multigene subfamily involved in xenobiotic metabolism, cytochrome P450 2B (CYP2B).

Efficacy of the LouseBuster, a new medical device for treating head lice (Anoplura:Pediculidae).

Human head lice (Pediculus humanus capitis De Geer) occur worldwide and infest millions of children and adults every year. Head lice infestations, which are known as pediculosis capitis, are psychologically stressful, physically irritating, and are one of the leading causes of K-6 school absence. The prevalence of head lice in many countries is increasing rapidly because of resistance to chemicals used in many head lice treatments.

Competition promotes the evolution of host generalists in obligate parasites.

Ecological theory traditionally predicts that interspecific competition selects for an increase in ecological specialization. Specialization, in turn, is often thought to be an evolutionary 'dead end,' with specialist lineages unlikely to evolve into generalist lineages. In host-parasite systems, this specialization can take the form of host specificity, with more specialized parasites using fewer hosts.

Host specialization differentiates cryptic species of feather-feeding lice.

Parasite species with differentiated host-specific populations provide a natural opportunity to explore factors involved in parasite diversification. Columbicola macrourae is a species of ectoparasitic feather louse currently recognized from 15 species of New World pigeons and doves. Mitochondrial sequences reveal five divergent haplotype clusters within C.

COMPARATIVE TRANSMISSION DYNAMICS OF COMPETING PARASITE SPECIES.

Competition-colonization trade-off models explain the coexistence of competing species in terms of a trade-off between competitive ability and the ability to colonize competitor-free patches of habitat. A simple prediction of these models is that inferior competitors will be superior dispersers. This prediction has seldom been tested in natural populations because measuring dispersal is difficult.

Host defence mediates interspecific competition in ectoparasites.

1. Interspecific competition influences which, how many and where species coexist in biological communities. Interactions between species in different trophic levels can mediate interspecific competition; e.