Experimental establishment of big-leaf mahogany (Swietenia macrophylla King) seedlings on two soil types in native forest of Pará, Brazil

Research into the mechanisms underlying edaphic associations reported for many tropical forest tree species, including those in the Meliaceae, has paid little attention to the earliest post-dispersal life stages. We conducted a reciprocal sowing experiment to examine germination and establishment rates of big-leaf mahogany (Swietenia macrophylla King) during the first seedling growing season in two local edaphic habitats in southeastern Amazonia. In this region, adult populations are restricted primarily to low-ground soils associated with seasonal streams, but rarely are found on high-ground soils. Soil analyses revealed that low-ground soils at the study site were silty loams whereas high-ground soils were clays. High-ground soils were less acidic and more fertile than low-ground soils, especially with respect to total nitrogen, Mg, and sum of basic cations.     

Age-related trends in red spruce foliar plasticity in relation to declining productivity

Phenotypic plasticity in needle morphology with increasing tree size and age was investigated by comparing four age classes of red spruce (Picea rubens Sarg.) ranging from juvenile (3-12 years old) to mature (over 100 years old). With increase in tree age there were significant increases in leaf mass per unit area (LMA), mesophyll and vascular bundle area as a percentage of total needle cross-sectional area, and stomatal density. Within the vascular bundle, both xylem cross-sectional area and tracheid lumen area increased significantly, whereas air space as a percentage of total cross-sectional area decreased. These morphological changes were associated with a significant decrease in photosynthetic capacity and stomatal conductance, and an increase in (13)C enrichment. Although both photosynthetic capacity and whole-tree conductance decreased significantly between age classes 3 and 12 years, they did not differ between age classes 53 and 127 years, even though needle (13)C enrichment was significantly greater in the 127-year age class. Thus there appear to be compensatory mechanisms that maintain photosynthetic capacity as trees increase in size and vascular complexity, which in red spruce and other species, may affect leaf hydraulic conductance. Although increased LMA may contribute to reduced photosynthetic capacity in red spruce, similar relationships are not seen in other conifers.     

Defining the Transition from Cell Elongation to Secondary Cell Wall Biosynthesis:Promoter Analyses,Transcript Profiling,and Genomic Analysis of Near-isogenic Germplasms that Differ in Fiber Strength

A distinct set of homoeologous cellulose synthase catalytic subunit (CesA) genes are coordinately up-regulated with the onset of secondary wall formation in cotton fiber as shown by quantitative-RTPCR.     

Ammonium and nitrate uptake, nitrogen productivity and biomass allocation in interior spruce families with contrasting growth rates and mineral nutrient preconditioning

Four full-sib families of interior spruce (Picea glauca (Moench) Voss) x Picea engelmanii Parry ex Engelm.) with contrasting growth rates (two fast-growing and two slow-growing families) were grown aeroponically with either a 2% relative nitrogen addition rate or free access to nitrogen. Fast-growing families showed greater plasticity in allocating biomass to shoots at high nitrogen supply and to roots at low nitrogen supply than slow-growing families. Compared with the slow-growing families, short-term net ammonium uptake rate measured with an ion selective electrode was significantly greater in fast-growing families at high ammonium supply, but not at low supply. Net nitrate uptake showed the same trend, but differences among families were not significant. Results indicate that differences in seedling growth rate are partly a result of physiological differences in net nitrogen uptake efficiency and nitrogen productivity.     

Systemic infection in European perch with thermoadapted virulent Aeromonas salmonicida (Perca fluviatilis)

In non‐salmonid fish, Aeromonas salmonicidacan cause local infections with severe skin ulcerations, known as atypical furunculosis. In this study, we present a systemic infection by a virulent A. salmonicidain European perch (Perca fluviatilis).This infection was diagnosed in a Swiss warm water recirculation aquaculture system. The isolate of A.  salmonicida encodes a type three secretion system (TTSS) most likely located on a plasmid similar to pAsa5/pASvirA, which is known to specify one of the main virulence attributes of the species A. salmonicida. However, the genes specifying the TTSS of the perch isolate show a higher temperature tolerance than strains isolated from cold‐water fish. The function of the TTSS in virulence was verified in a cytotoxicity test using bluegill fry and epithelioma papulosum cyprinid cells.     

Effect of line shooter and mainline tension on the sink rates of pelagic longlines and implications for seabird interactions

1. The likelihood that seabirds will be hooked and drowned in longline fisheries increases when baited hooks sink slowly. Fishermen target different fishing depths by setting the mainline through a line shooter, which controls the tension (or slackness) in the line. An experiment was conducted in Australia's pelagic longline fishery to test the hypothesis of no difference in sink rates of baited hooks attached to mainline set under varying degrees of tension. 2. Mainline was set in three configurations typically used in the fishery: (a) surface set tight with no slackness astern; (b) surface set loose with 2 s of slack astern; and (c) deep set loose with 7 s of slack astern. 3. Tension on the mainline had a powerful effect on sink rates. Baited hooks on branch lines attached to tight mainlines reached 2 m depth nearly twice as fast as those on the two loose mainline tensions, averaging 5.8 s (0.35 m s^?1) compared with 9.9 s (0.20 m s^?1) and 11.0 s (0.18 m s^?1) for surface set loose and deep set loose tensions, respectively. 4. The likely reason for the difference is propeller turbulence. Tight mainline entered the water aft of the area affected by turbulence whereas the two loose mainlines and the clip ends of branch lines were set directly into it about 1 m astern of the vessel. The turbulence presumably slowed the sink rates of baited hooks at the other end of the branch lines. 5. The results suggest that mainline deployed with a line shooter (as in deep setting) into propeller turbulence at the vessel stern slows the sink rates of baited hooks, potentially increasing their availability to seabirds. Unless mainline can be set to avoid propeller turbulence the use of line shooters for deep setting should not be promoted as an effective deterrent to seabirds. Copyright © 2010 John Wiley & Sons, Ltd.     

Development of a dot blot assay for the rapid detection of central nervous system tissue on meat and contact surfaces

As a potential transmitter of bovine spongiform encephalopathy (BSE), tissue from bovine central nervous system (CNS) is not accepted in meat and meat products. Western blot analysis of the CNS marker myelin proteolipid protein (PLP) detects CNS contamination selectively and sensitively. In this study, a rapid dot blot assay using an anti-PLP antibody was developed to screen CNS contamination of meat and contact surfaces. The detection limit was 0.01% bovine brain in minced bovine muscle. When applied to a swab test, down to 0.5 mg of CNS tissue on meat or other surfaces was detectable. Other offal tissues or peripheral nerves did not interfere with the assay. The test allows a differentiation between mammalian and avian CNS but not among mammalian species. The swab test was applied immediately after slaughtering at several areas of the bovine head. CNS was not detectable at any region which may enter the food chain.     

Impact of the 2014–2016 marine heatwave on US and Canada West Coast fisheries: Surprises and lessons from key case studies

Marine heatwaves are increasingly affecting marine ecosystems, with cascading impacts on coastal economies, communities, and food systems. Studies of heatwaves provide crucial insights into potential ecosystem shifts under future climate change and put fisheries social-ecological systems through “stress tests” that expose both vulnerabilities and resilience. The 2014–16 Northeast Pacific heatwave was the strongest and longest marine heatwave on record and resulted in profound ecological changes that impacted fisheries, fisheries management, and human livelihoods. Here, we synthesize the impacts of the 2014–2016 marine heatwave on US and Canada West Coast fisheries and extract key lessons for preparing global fisheries science, management, and industries for the future. We set the stage with a brief review of the impacts of the heatwave on marine ecosystems and the first systematic analysis of the economic impacts of these changes on commercial and recreational fisheries. We then examine ten key case studies that provide instructive examples of the complex and surprising challenges that heatwaves pose to fisheries social-ecological systems. These reveal important insights into improving the resilience of monitoring and management and increasing adaptive capacity to future stressors. Key recommendations include: (1) expanding monitoring to enhance mechanistic understanding, provide early warning signals, and improve predictions of impacts; (2) increasing the flexibility, adaptiveness, and inclusiveness of management where possible; (3) using simulation testing to help guide management decisions; and (4) enhancing the adaptive capacity of fishing communities by promoting engagement, flexibility, experimentation, and failsafes. These advancements are important as global fisheries prepare for a changing ocean.     

MALIGNANT PERIPHERAL NERVE SHEATH TUMOR IN A CAT

A report of a cat with a cranial tumor of nerve sheath origin is presented. The cranial mass, with a cyst-like character on presentation to the referring veterinarian suggested a benign lesion, but the clinical course was rapid and indicative of central nervous system involvement. The tumor was poorly differentiated by histologic examination, but immunohistochemistry was consistent with Schwann cell origin. Features of peripheral nerve sheath tumors in cats and other species are briefly discussed.