Characterization of the hepcidin gene in eight species of bats

Hemochromatosis, or iron storage disease, has been associated with significant liver disease and mortality in captive Egyptian fruit bats (Rousettus aegyptiacus). The physiologic basis for this susceptibility has not been established. In humans, a deficiency or resistance to the iron regulatory hormone, hepcidin has been implicated in the development of hereditary hemochromatosis. In the present study, we compared the coding sequence of the hepcidin gene in eight species of bats representing three distinct taxonomic families with diverse life histories and dietary preferences. Bat hepcidin mRNA encoded a 23 amino acid signal peptide, a 34 or 35 amino acid pro-region, and a 25 amino acid mature peptide, similar to other mammalian species. Differences in the sequence of the portion of the hepcidin gene that encodes the mature peptide that might account for the increased susceptibility of the Egyptian fruit bat to iron storage disease were not identified. Variability in gene sequence corresponded to the taxonomic relationship amongst species.     

Metastatic anaplastic adenocarcinoma suspected to be of mammary origin in an intact male rabbit (Oryctolagus cuniculus)

A 7-year-old, intact male, pet dwarf rabbit (Oryctolagus cuniculus) was presented for a ventral abdominal subcutaneous mass. Histolopathology of the resected mass was suggestive of a mammary adenocarcinoma. Six months later, the rabbit died from severe dyspnea. Necropsy showed recurrence of the original mass with hepatic and pulmonary metastasis of the anaplastic adenocarcinoma, suspected to be of mammary origin.     

Sex differences in the influence of social context,salient social stimulation and amphetamine on ultrasonic vocalizations in prairie voles

Prairie voles (Microtus ochrogaster) are a socially monogamous rodent species and their cooperative behaviors require extensive communication between conspecifics. Rodents use ultrasonic vocalizations (USVs) to communicate and because a prairie vole breeder pair must engage in extensive cooperation for successful reproduction, auditory communication may be critical for this species. Therefore, we sought to characterize USVs in adult male and female prairie voles, and to determine how these calls are influenced by social context, salient social stimuli and the psychostimulant drug of abuse amphetamine (AMPH). Here, we characterize prairie vole USVs by showing the range of frequencies of prairie vole USVs, the proportion of various call types, how these call types compare between males and females, and how they are influenced by social stimulation and AMPH. AMPH caused a robust increase in the number of USVs in both males and females and there was a dramatic sex difference in the complexity of call structures of AMPH‐induced USVs, with males emitting more elaborate calls. Moreover, we show that novel (i.e. salient) social cues evoked differential increases in USVs across sex, with males showing a much more robust increase in USV production, both with respect to the frequency and complexity of USV production. Exposure to an estrous female in particular caused an extraordinary increase in USVs in male subjects. These data suggest that USVs may be a useful measure of social motivation in this species, including how social behaviors can be impacted by drugs of abuse.     

Constraints and time lags for recovery of a keystone species (Dipodomys spectabilis) after landscape restoration

Habitat restoration is typically focused on reestablishing suitable conditions at a local scale, but landscape constraints may be important for keystone species with limited dispersal. We tested for time lags and examined the relative importance of local and landscape constraints on the response of the banner-tailed kangaroo rat (Dipodomys spectabilis) to restoration of Chihuahuan Desert grasslands in New Mexico, USA. Dipodomys spectabilis is a keystone species that creates habitat heterogeneity and modifies the structure of plant and animal communities. We selected 21 sites and compared density of D. spectabilis between areas treated with herbicide to control shrubs (treated areas) and paired untreated areas. We evaluated whether density of D. spectabilis depended on treatment age, local habitat quality (vegetation and soil structure), and landscape factors (treatment area and spatial connectivity). Density was greater at treated areas than at untreated areas due to a direct effect of reduced shrub cover. However, the response of D. spectabilis to restoration was lagged by a decade or more. Structural equation modeling indicated the time lag reflected a dispersal constraint as opposed to a temporal change in habitat quality. This inference was corroborated by a positive relationship between density at treated areas and connectivity to source populations. Our results indicate that density of D. spectabilis depended strongly on the spatial configuration of treated areas, which supports a landscape mosaic approach to restoration. If keystone species commonly exhibit limited dispersal ability, landscape constraints may be broadly important for shaping ecosystem structure and function after habitat restoration.     

Early forest dynamics in stand-replacing fire patches in the northern Sierra Nevada, California, USA

There is considerable concern over the occurrence of stand-replacing fire in forest types historically associated with low- to moderate-severity fire. The concern is largely over whether contemporary levels of stand-replacing fire are outside the historical range of variability, and what natural forest recovery is in these forest types following stand-replacing fire. In this study we quantified shrub characteristics and tree regeneration patterns in stand-replacing patches for five fires in the northern Sierra Nevada. These fires occurred between 1999 and 2008, and our field measurements were conducted in 2010. We analyzed tree regeneration patterns at two scales: patch level, in which field observations and spatial data were aggregated for a given stand-replacing patch, and plot level. Although tree regeneration densities varied considerably across sampled fires, over 50 % of the patches and approximately 80 % all plots had no tree regeneration. The percentage of patches, and to a greater extent plots, without pine regeneration was even higher, 72 and 87 %, respectively. Hardwood regeneration was present on a higher proportion of plots than either the pine or non-pine conifer groups. Shrub cover was generally high, with approximately 60 % of both patches and individual plots exceeding 60 % cover. Patch characteristics (size, perimeter-to-area ratio, distance-to-edge) appeared to have little effect on observed tree regeneration patterns. Conifer regeneration was higher in areas with post-fire management activities (salvage harvesting, planting). Our results indicate that the natural return of pine/mixed-conifer forests is uncertain in many areas affected by stand-replacing fire.     

Selection on major components of angiosperm genomes

Angiosperms are a relatively recent evolutionary innovation, but their genome sizes have diversified remarkably since their origin, at a rate beyond that of most other taxa. Genome size is often correlated with plant growth and ecology, and extremely large genomes may be limited both ecologically and evolutionarily. Yet the relationship between genome size and natural selection remains poorly understood. The manifold cellular and physiological effects of large genomes may be a function of selection on the major components that contribute to genome size, such as transposable elements and gene duplication. To understand the nature of selection on these genomic components, both population-genetic and comparative approaches are needed.     

A survey of the skidder fleet of Central,Eastern and Southern Europe

European Journal of Forest Research - As a generalization, harvested timber is extracted from forests either as trees or stems by skidders or as logs by forwarders. Coupled with harvesters,...