Biological control of intolerant hardwood competition: Silvicultural efficacy of Chondrostereum purpureum and worker productivity in conifer plantations

The vigorous vegetative reproduction of intolerant deciduous competition limits the efficacy of mechanical release operations in young softwood plantations. Applying bioherbicides such as the fungus Chondrostereum purpureum (Pers. ex Fr.) Pouzar could improve the effectiveness of release by reducing stump sprouting while gaining public acceptance. A field experiment was conducted in Québec (Canada) in two white spruce (Picea glauca [Moench] Voss) plantations invaded by intolerant hardwoods. This study compared four-year response of traditional mechanical release and mechanical release with an application of C. purpureum under the commercial formulation Myco-Tech™. The general objective of the project was to measure the silvicultural efficacy and worker productivity related to applying C. purpureum to control intolerant hardwoods in young white spruce plantations.     

Differential impact of chronic ozone exposure on expanding and fully expanded poplar leaves

Populus tremula L. × Populus alba L. (Populus ×c anescens (Aiton) Smith) - clone INRA 717-1-B4 saplings (50 cm apex to base and carrying 19 leaves on average) - were followed for 28 days. Half of the trees were grown in charcoal-filtered air while the other half were exposed to 120 ppb ozone for 11 h a day during the light period. The expanding leaf number 4 was tagged at the beginning of the experiment and finished expansion between 7 and 14 days. These leaves were harvested weekly for biochemical and proteome analyses using quantitative bidimensional electrophoresis (DiGE). Independent of the ozone treatment, all the analyses allowed a distinction between expanding and adult leaves. The results indicate that during the expansion phase (Days 0-7) the enzymatic machinery of the leaves is set up, and remains dynamically stable in the adult leaves (Days 14-28). Although ozone had no apparent effect on expanding leaves, the metabolic stability in fully expanded leaves observed in ozone-free plants was disturbed after 2 weeks of exposure and a stress-induced response became apparent.     

Initial distance to Kalmia angustifolia as a predictor of planted conifer growth

New Forests - In the Canadian boreal forest, conifer plantations are mainly used to overcome poor natural regeneration following harvesting or wildfires. However, competitive interactions can...     

A comparison of nanoindentation cell wall hardness and Brinell wood hardness in jack pine (Pinus banksiana Lamb.)

Nanoindentation is a powerful tool for hardness testing on a very small scale. Since the technique was first introduced for studying wood cell wall mechanics, it has been integrated as an important tool for measuring the modulus of elasticity and hardness of wood cell walls. In this study, hardness measured with nanoindentation (nanohardness) was compared with hardness measured by the standard Brinell test method (Brinell hardness) on jack pine (Pinus banksiana Lamb.) wood. Nanoindentation was performed on both the S2 layer of the secondary cell wall and the middle lamella (ML) of early- and latewood fibers. Four annual growth rings were studied. The influence of growth ring and initial spacing on both measurements was analyzed. The relationship between Brinell hardness, nanoindentation measurements, and average ring density was also studied. Results suggest that Brinell- and nanohardness are controlled by different mechanisms and factors. The location of nanohardness measurements (i.e., S2 layer or ML) also influenced hardness differently. It was concluded that nanomeasurements are not an exact representation of wood mechanical properties conducted at the macro level because of the hierarchical structure of wood. The effect of other factors such as moisture or wood extractive content may also need consideration.     

The Marine-Derived Kinase Inhibitor Fascaplysin Exerts Anti-Thrombotic Activity

Background: The marine-derived kinase inhibitor fascaplysin down-regulates the PI3K pathway in cancer cells. Since this pathway also plays an essential role in platelet signaling, we herein investigated the effect of fascaplysin on thrombosis. Methods: Fascaplysin effects on platelet activation, platelet aggregation and platelet-leukocyte aggregates (PLA) formation were analyzed by flow cytometry. Mouse dorsal skinfold chambers were used to determine in vivo the effect of fascaplysin on photochemically induced thrombus formation and tail-vein bleeding time. Results: Pre-treatment of platelets with fascaplysin reduced the activation of glycoprotein (GP)IIb/IIIa after protease-activated receptor-1-activating peptide (PAR-1-AP), adenosine diphosphate (ADP) and phorbol-12-myristate-13-acetate (PMA) stimulation, but did not markedly affect the expression of P-selectin. This was associated with a decreased platelet aggregation. Fascaplysin also decreased PLA formation after PMA but not PAR-1-AP and ADP stimulation. This may be explained by an increased expression of CD11b on leukocytes in PAR-1-AP- and ADP-treated whole blood. In the dorsal skinfold chamber model of photochemically induced thrombus formation, fascaplysin-treated mice revealed a significantly extended complete vessel occlusion time when compared to controls. Furthermore, fascaplysin increased the tail-vein bleeding time. Conclusion: Fascaplysin exerts anti-thrombotic activity, which represents a novel mode of action in the pleiotropic activity spectrum of this compound.     

Rib osteoblastic osteosarcoma in an African hedgehog (Atelerix albiventris).

A 3-year-old African hedgehog (Atelerix albiventris) was presented to the Exotic Animal Clinic of the University of Montreal for evaluation of a mass growing on the right thoracic wall. The diagnostic workup, which included helical computed tomography, confirmed the presence of a large mass, originating from the right 7th rib, infiltrating the thoracic wall and cavity. The animal was euthanized due to the poor prognosis. At necropsy, a well-demarcated mass penetrated the thoracic wall and incorporated the 6th to 8th ribs. Cut sections of the tumor were white, glistening, firm, and gritty. Microscopically, it was composed of polyhedral to elongated cells with interspersed trabeculae of osteoid and large areas of coagulative necrosis. On the basis of histopathologic findings, a diagnosis of osteoblastic osteosarcoma was made. To the authors' knowledge, this is the first report of an osteoblastic osteosarcoma on the thoracic wall of an African hedgehog, as well as the first report of the use of helical computed tomography in that species.     

Myxedema coma leading to respiratory depression in a dog

A 10-year-old, intact male, cocker spaniel was presented with hypothermia, without shivering, and progressive stupor leading to coma. Myxedema coma, potentially precipitated by diuretic therapy, was tentatively diagnosed and treatment initiated, but progressive respiratory depression led to the decision to euthanize. Postmortem findings supported the diagnosis of myxedema coma.