Carbohydrate transfer through root grafts to support shaded trees

We investigated whether root grafts between lodgepole pine (Pinus contorta var. latifolia Dougl. ex. Loud.) trees can transfer sufficient carbohydrate reserves from a source tree to a grafted sink tree to affect the vigor of trees growing in a light-limited environment. Eleven plots were established in early spring and two grafted tree pairs and two independent non-grafted trees were selected at each plot. One tree in a grafted pair and one non-grafted tree were shaded at each plot, whereas the remaining trees were non-shaded during the experimental period. Shaded trees had significantly lower carbohydrate reserves and smaller crowns than non-shaded trees following one growing season. Grafted shaded trees had significantly higher root total nonstructural carbohydrate concentrations than non-grafted shaded trees, indicating that root grafts partially offset the effects of shading. Also, large root grafts transferred proportionately more carbohydrates to the shaded trees than small root grafts. Carbohydrates transferred through root grafts could allow grafted trees to persist under conditions where non-grafted trees would be removed by competition.     

Broad spectrum antimicrobial activity of leukocyte extracts from the American alligator (Alligator mississippiensis)

Leukocytes were isolated from whole blood of wild alligators by differential sedimentation. The leukocytes were disrupted in 5% AcOH and the crude extracts processed by ultrafiltration. The extracts were subjected to solvent exchange (0.1% AcOH) and the fraction that contained macromolecules between 1 and 10 kDa were subjected to further analyses. The acid extracts of the alligator leukocytes exhibited substantial antimycotic activities against six of eight species of Candida yeast tested. In addition, the alligator leukocyte extracts were effective as antimicrobial agents against 10 of 12 bacterial species, and displayed moderate activity against two enveloped viruses (human immunodeficiency virus-1 and herpes simplex virus-1_HF). Kinetic analyses revealed that the antimycotic effects of the leukocyte extract occurred rapidly, with 64% fungal growth inhibition within 3 min of exposure. The molecule(s) responsible for the antimicrobial activities were sensitive to proteases, heat-stable, acid soluble, and in the 1–10 kDa range. These data suggest that alligator leukocytes express cationic peptides that are responsible for their antimicrobial properties.     

Landscape resistance and American marten gene flow

Landscape heterogeneity can influence animal dispersal by causing a directional bias in dispersal rate, as certain landscape configurations might promote, impede, or prevent movement and gene flow. In forested landscapes, logging operations often contribute to heterogeneity that can reduce functional connectivity for some species. American martens (Martes americana) are one such species, as they are considered specialists of late-seral coniferous forests. We assessed marten gene flow to test the hypothesis that habitat management has maintained landscape connectivity for martens in the managed forests of Ontario, Canada. We genotyped 653 martens at 12 microsatellite loci, sampled from 29 sites across Ontario. We expected that if forest management has an effect on marten gene flow, we would see a correlation between effective resistance, estimated by circuit theory, and genetic distance, estimated by population graphs. Although we found a positive relationship between effective resistance and genetic distance (Mantel r = 0.249, P < 0.001), marten gene flow was better described by isolation by Euclidean distance (Mantel r = 0.410, P < 0.001). Our results suggest that managed forests in Ontario are well connected for marten and neither impede nor promote marten gene flow at the provincial scale.     

A case series of thermal scald injuries in dogs exposed to hot water from garden hoses (garden hose scalding syndrome)

In this report, we present a series of cases of thermal burns (scalds) in dogs resulting from exposure to hot water from a garden hose that had been lying in the sun. These dogs typically inhabited the southern and western regions of the USA, where the recorded high temperatures often exceed 32°C (90°F) during the warm summer months. Dogs with thermal scald injury in these cases presented with linear thermal burns along the dorsum, in addition to a variety of other macroscopic lesions that were dependent upon the degree of burn exposure and ranged from local erythema to ulcerated, necrotic and sloughing skin. Chronic, healed wounds were often alopecic, with markedly thickened skin and characteristically smooth and glassy scar tissue formation. Histologically, the lesions of thermal scald injury in these dogs were indistinguishable from any other second or third degree burn, and consisted of full-thickness dermal and epidermal necrosis with occasional fibrinoid necrosis of vessel walls, vasculitis and intravascular thrombosis. Here, we closely examine 10 cases of dogs with dorsal thermal burns collected from Texas, Arizona, California, Utah, Nevada, Indiana, Michigan and North Carolina and propose the term 'garden hose scalding syndrome (GHS)' to describe this unique type of scald injury.     

Estimates of prevalence of hip dysplasia in Golden Retrievers and Rottweilers and the influence of bias on published prevalence figures

OBJECTIVE: To estimate prevalence of canine hip dysplasia (CHD) in Golden Retrievers and Rottweilers and identify sources of bias in published reports. DESIGN: Prospective study. ANIMALS: 200 clinically normal Golden Retrievers and 140 clinically normal Rottweilers between 24 and 60 months of age referred for hip evaluation (group 1) and 93 clinically normal dogs evaluated for Orthopedic Foundation for Animals (OFA) hip certification (group 2). PROCEDURE: Hip-extended pelvic radiographs from group 1 dogs were screened for CHD. Radiographs were evaluated twice; the first interpretation used an OFA-type subjective 7-point scoring system, and the second included the caudolateral curvilinear osteophyte as an additional sign of degenerative joint disease. The OFA submission rate of group 2 dogs was determined from the number of official reports returned from the OFA. RESULTS: Prevalence of CHD in Golden Retrievers ranged from 53% to 73% and in Rottweilers ranged from 41% to 69%. Among dogs referred for OFA evaluation, radiographs from 49 (53%) were submitted to OFA. Of submitted radiographs, 45 (92%) were normal; of radiographs not submitted, 22 (50%) were normal. Radiographs with normal-appearing hips were 8.2 times as likely to be submitted to the OFA. Compared with Golden Retrievers, Rottweiler radiographs were significantly more likely to be submitted for OFA certification. CONCLUSIONS AND CLINICAL RELEVANCE: Prevalence of CHD in these 2 breeds may be much higher than previously reported in the United States. Results suggest substantial bias in the OFA database, which causes lower estimates of prevalence of CHD.     

Perspectives on emerging zoonotic disease research and capacity building in Canada

Zoonoses are fundamental determinants of community health. Preventing, identifying and managing these infections must be a central public health focus. Most current zoonoses research focuses on the interface of the pathogen and the clinically ill person, emphasizing microbial detection, mechanisms of pathogenicity and clinical intervention strategies, rather than examining the causes of emergence, persistence and spread of new zoonoses. There are gaps in the understanding of the animal determinants of emergence and the capacity to train highly qualified individuals; these are major obstacles to preventing new disease threats. The ability to predict the emergence of zoonoses and their resulting public health and societal impacts are hindered when insufficient effort is devoted to understanding zoonotic disease epidemiology, and when zoonoses are not examined in a manner that yields fundamental insight into their origin and spread. Emerging infectious disease research should rest on four pillars: enhanced communications across disciplinary and agency boundaries; the assessment and development of surveillance and disease detection tools; the examination of linkages between animal health determinants of human health outcomes; and finally, cross-disciplinary training and research. A national strategy to predict, prevent and manage emerging diseases must have a prominent and explicit role for veterinary and biological researchers. An integrated health approach would provide decision makers with a firmer foundation from which to build evidence-based disease prevention and control plans that involve complex human/animal/environmental systems, and would serve as the foundation to train and support the new cadre of individuals ultimately needed to maintain and apply research capacity in this area.