Occurrence and range of dicumarol concentrations in sweet clover

The dicumarol concentration in 272 cured sweet clover samples from 4 counties in North Dakota was determined. Dicumarol concentrations ranged from 0 to 164.7 mg/kg of sweet clover, with 64.6% of the 272 samples containing less than 10 mg/kg. Round bales were significantly (P less than 0.05) higher in dicumarol concentration (mean of 22.9 +/- 3.10 mg/kg) than were stacks or silage (means of 1.8 +/- -6.3 mg/kg and 0.6 +/- 2.1 mg/kg, respectively). The outer section of core samples taken from round bales contained significantly (P less than 0.0021) higher concentrations of dicumarol than did the inner section of the core, with means of 30.8 mg/kg and 16.6 mg/kg, respectively. A significant (P less than 0.0001) correlation existed between crude protein and dicumarol values (r = 0.44).     

Gastric absorption of a pesticide (1-naphthyl N-methylcarbamate) in the fasted rat

The gastric absorption of [1-naphthyl-1-¹⁴C]N-methylcarbamate (radiolabeled carbaryl) administered intragastrically (7.5 μmoles/kg body wt) to fasted, anesthetized female rats was investigated by measurement of ¹⁴C absorption and by identification of the radiolabeled constituents in the portal blood. At 22 and 67 min after dosing, 52.6 ± 14.1% (n = 3) and 81.7 ± 15.7% (n = 3), respectively, of the ¹⁴C was absorbed from the stomachs (ligated pylori) of rats with intact portal circulation. In another experiment, 69.1 ± 25.9% (n = 3) of the ¹⁴C was absorbed from the rat stomachs (ligated pylorus and esophagus) during 66.0 ± 1.0 min of total portal blood collection (via an in vivo perfusion technique). The radiolabeled material in the collected portal blood accounted for 97.2 ± 1.9% (n = 3) of the ¹⁴C absorbed from rat stomachs. On the basis of thin-layer chromatography, gas chromatography, and infrared spectroscopy, 89.3% of the radiolabeled material in the collected portal blood was [1-naphthyl-1-¹⁴C]N-methylcarbamate.     

Saturation of the southern ocean CO2 sink due to recent climate change

Based on observed atmospheric carbon dioxide (CO2) concentration and an inverse method, we estimate that the Southern Ocean sink of CO2 has weakened between 1981 and 2004 by 0.08 petagrams of carbon per year per decade relative to the trend expected from the large increase in atmospheric CO2. We attribute this weakening to the observed increase in Southern Ocean winds resulting from human activities, which is projected to continue in the future. Consequences include a reduction of the efficiency of the Southern Ocean sink of CO2 in the short term (about 25 years) and possibly a higher level of stabilization of atmospheric CO2 on a multicentury time scale.     

ABAD directly links Abeta to mitochondrial toxicity in Alzheimer's disease

Mitochondrial dysfunction is a hallmark of beta-amyloid (Abeta)-induced neuronal toxicity in Alzheimer's disease (AD). Here, we demonstrate that Abeta-binding alcohol dehydrogenase (ABAD) is a direct molecular link from Abeta to mitochondrial toxicity. Abeta interacts with ABAD in the mitochondria of AD patients and transgenic mice. The crystal structure of Abeta-bound ABAD shows substantial deformation of the active site that prevents nicotinamide adenine dinucleotide (NAD) binding. An ABAD peptide specifically inhibits ABAD-Abeta interaction and suppresses Abeta-induced apoptosis and free-radical generation in neurons. Transgenic mice overexpressing ABAD in an Abeta-rich environment manifest exaggerated neuronal oxidative stress and impaired memory. These data suggest that the ABAD-Abeta interaction may be a therapeutic target in AD.     

Immunhistologische Untersuchungen über das Vorkommen von Kartoffelblattrollvirus in Knolle und Spross der Kartoffelpflanze

Zusammenfassung Kartoffelblattrollvirus (PLRV) wurde mit der Immunofluoreszenztechnik in der Kartoffelknolle und in oberirdischen Pflanzenteilen nachgewiesen. PLRV wurde dabei stets im Phloem, niemals in parenchymatischen Geweben aufgefunden. Am Kronenende der Knolle erh?hte sich der PLRV-Gehalt nach der Keimung zusammen mit der Vermehrung der Phloemzellen. Der verh?ltnism?ssig hohe Virusgehalt am Nabelende blieb von der Keimung unbeeinflusst. PLRV wurde auch im Phloem der Stengel und Bl?tter nachgewiesen. In der Knospe war PLRV nur selten aufzufinden.

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Summary Potato Leaf Roll Virus was detected by an immunofluorescent technique in tubers and above ground parts of the potato plant. For the production of antisera, PLRV was multiplied inPhysalis floridana plants and the virus purified according to the method of Takanami & Kubo (1979). Microtome sections were prepared from secondary infested tubers and shoots grown from eye plugs of the cultivar Sieglinde. The virus was detected successfully in 15 μm thick sections of unfixed tissue cut on a freezing microtome. For indirect antigen detection the sections were first treated with specific antiserum, incubated with FITC conjugated anti-rabbit globulin and evaluated by UV fluorescence microscopy. PLRV was persistent in the area of the vascular bundles, but was never detected in parenchymatous tissue. The limits of the fluorescent area at the rose end of the tuber were dependent on the stage of development of the eyes. The dormant eyes were, with the exception of a few phloem cells, largely free of fluorescence (Fig. 1a). As the eyes grew and the phloem developed, FITC fluorescence increased (Fig. 1b, 1c). The fluorescence in the area of the vascular bundles was noticeably stronger lower down, indicating that the basal portion of the eyes contained more PLRV than the apical region. High fluorescence intensity was always found at the heel end of the tubers, whether they were dormant or sprouting (Fig. 2a, b). Therefore the PLRV levels in dormant tubers is higher at the heel than at the rose end. This difference is not apparent and may even be reversed at the rose end in sprouting tubers, because of the development of phloem and its associated viral multiplication. PLRV was detected in the phloem in cross-sections of both the stems and leaves of eye shoots (Figs 3 and 4). In the buds the green fluorescence showed only in a few developing phloem cells indicating PLRV infection (Fig. 5).

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Résumé Le virus de l'enroulement (PLRV) a été décelé dans le tubercule de pomme de terre, ainsi que dans les organes aériens, avec l'aide de la technique de l'immunofluorescence. Le PLRV a été multiplié dans les plantes dePhysalis floridana pour la production de l'antisérum. La purification du virus a été faite selon la méthode Takanami et Kubo (1979). Pour les coupes au microtome, des tubercules et plantes issus d'oeilletons de la variété Sieglinde, porteurs de PLRV d'une infection secondaire, ont été utilisés. Le virus a été décelé sur des coupes de 15 μm à partir de tissus non fixés. Pour le contr?le indirect de l'antigène, les coupes étaient d'abord mises en incubation avec un antisérum spécifique, ensuite avec des anticorps spécifiques d'anticorps lapin marqués au FITC et examinés avec un microscope fluorescent. Le PLRV a régulièrement été décelé dans la région des faisceaux, et jamais dans le tissu parenchymatique. A la couronne, l'intensité de la fluorescence dépendait du stade de développement des tubercules. L'oeil dormant ne présentait pratiquement pas de fluorescence à l'exception de quelques cellules du phloème (fig. 1a). Avec l'évolution de la germination de l'oeil et la multiplication du phloème, la fluorescence FITC augmentait (fig. 1b, 1c). Etonnament, la partie inférieure des faisceaux présentait une fluorescence plus intense que la partie supérieure. On peut s'attendre à ce que le taux de PLRV soit plus élevé dans la région basale de l'oeil que dans les extrémités. Dans la région de l'ombilic, la fluorescence était plus élevée dans tous les cas, tant pour les tubercules dormants que pour les tubercules en germination (fig. 2a, 2b). Le taux de PLRV est par conséquent plus élevé dans la partie de l'ombilic qu'à la couronne pour des tubercules en dormance. Sur le tubercule en germination, cette différence peut être nivelée ou même s'inverser en raison de la multiplication du phloème et du virus. Sur la jeune pousse d'oeilleton, le PLRV a été décelé dans la tige et dans le phloème d'une coupe transversale de feuille (fig. 3, 4). L'infection du bourgeon par le PLRV ne présente qu'une faible fluorescence verte due à quelques cellules de phloème infiltrées (fig. 5).

     

Variations of Phosphorus Release from Sediments in Stratified Lakes

The aim of this investigation was to study the temporal variation in phosphorus release from the sediments and its influence on water quality of stratified lakes. The concentrations of soluble reactive phosphorus (SRP), calcium and sulfate in the interstitial water and the pH in the wet sediments of dimictic lakes were investigated during the spring circulation and at the end of summer stratification. Multiple regression analysis using the calculated diffusive fluxes of SRP out of the sediments and the morphometric characteristics of the lakes (reduced water depth), explained 73 % of the variance of the SRP-accumulation in the hypolimnia during summer stagnation. At the end of surnmer stratification diffusive fluxes of SRP out of the sediments increased and pH-values and sulfate-concentrations decreased at the sediment surface (0–2 em) and in the hypolimnia. The maximum diffusive flux of SRP was calculated to be 5.8 mg/m²/d at the end of summer stagnation. Prob able reasons for these higher diffusive fluxes of SRP at the end of summer stagnation are higher supply of labile organic matter and thereby higher mineralization rates. lower redox potential and thus higher dissolution of redox sensitive P-binding forms and/or dissolution of phosphorus being bound to Ca-phases at lower pH.     

Pharmacokinetics of intra‐articular morphine in horses with lipopolysaccharide‐induced synovitis

ObjectiveTo describe the pharmacokinetics of intra-articularly (IA) administered morphine.Study designExperimental randomized, cross-over study.AnimalsEight adult healthy mixed breed horses aged 6.5 ± 2.3 (mean ± SD) years and weighing 535 ± 86 kg.MethodsUnilateral radiocarpal synovitis was induced by IA injection of 3 μg lipopolysaccharide (LPS) on two occasions (right and left radiocarpal joint, respectively) separated by a 3-week wash-out period. Treatments were administered 4 hours post-LPS-injection: Treatment IA; preservative free morphine IA (0.05 mg kg^?1) plus saline intravenous (IV) and treatment IV; saline IA plus preservative free morphine IV (0.05 mg kg^?1). Concentrations of morphine, morphine-3-glucuronide and morphine-6-glucuronide (M6G) were determined repeatedly in serum and synovial fluid (SF) by high-performance liquid chromatography mass spectrometry, at 2 and 4 hours and then at 4 hours intervals until 28 hours post-treatment.ResultsInjection of LPS elicited a marked and comparable synovitis in all LPS-injected radiocarpal joints. IA administered morphine was detectable in SF of all eight joints 24 hours post-treatment and in 6/8 joints 28 hours post-treatment. The terminal half-life of morphine in SF was estimated to be 2.6 hours. IA administration of morphine resulted in mean serum concentrations of morphine below 5 ng mL^?1 from 2 to 28 hours after treatment.Conclusions and clinical relevanceIntra-articularly administered morphine remained within the joint for at least 24 hours. At the same time only very low serum concentrations of morphine and M6G were detected. The present results suggest that IA morphine at 0.05 mg kg^?1 may be used for IA analgesia lasting at least 24 hours and give strong support to the theory that previously observed analgesic and anti-inflammatory effects of IA morphine in horses are most likely to be mediated peripherally.     

Preference of foraging ants (Hymenoptera: Formicidae) for bait toxicants in South African vineyards

Argentine ants Linepithema humile (Mayr), common pugnacious ants Anoplolepis custodiens (F. Smith) and cocktail ants Crematogaster peringueyi Emery are the main indirect ant pests in South African vineyards. These ants form mutualistic relationships with the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), an economic phloem-feeding pest of vines that excretes honeydew. Ants feed on the honeydew from mealybugs and also affect predator-prey interactions by protecting them from attack by natural enemies. This consequently reduces the efficacy of predators and parasitic Hymenoptera in controlling P. ficus. Current strategies for ant control are limited to the application of long term residual insecticides that are detrimental to the environment, labour intensive to apply and potentially disruptive to biological control. Here, we report on the development of an alternative method of ant control using baits which are likely to show delayed toxicity to these ant species. Field bait preference assessments were carried out during spring, summer and autumn in three vineyards of the Cape Winelands region, Republic of South Africa during 2007/08. Preference/non-preference is the first behaviour an ant exhibits when encountering bait and this was measured in terms of numbers of ants at bait stations. Five toxicants comprising Gourmet ant bait (containing 0.5% boric acid as active ingredient and a honeydew mimic as an attractant), boric acid (0.5%), fipronil (0.0001%), fenoxycarb (0.5%) and spinosad (0.01%) all dissolved in 25% sucrose solution were tested against a 25% sucrose solution control. Gourmet ant bait was overall the most preferred bait during spring, summer and autumn, and on some occasions being significantly more preferable to ants than the control solution.     

Ectomycorrhizal community and extracellular enzyme activity following simulated atmospheric N deposition

Ectomycorrhizal (EM) fungi are abundant in temperate and boreal ecosystems and are understood to be an important means whereby plants can fulfill their nutrition requirements. The extent of the EM fungal involvement in accessing organic sources of N, however, remains unknown. Some EM fungi have been found to produce lignolytic and proteolytic enzymes which are necessary to depolymerize organic substrates, but this ability varies by species. Both EM fungal communities and the activities of lignolytic and proteolytic enzymes may be sensitive to changes in inorganic N availability such as through increased atmospheric deposition. Our objectives were to simulate an ecologically relevant increase in atmospheric N deposition in areas currently receiving very little exogenous N and examine changes in EM community composition, lignin degrading enzyme activity, and soil protein depolymerization. We found a distinct shift in the EM community composition following simulated atmospheric N deposition. Likewise, we found a significant decrease in the activity of lignin degrading enzymes, which could have important implications on ecosystem N and C cycling. Contrary to our hypotheses, proteolysis increased following N addition. The fact that lignolytic and proteolytic enzymes exhibit opposite responses is counterintuitive and suggests much is yet to be learned about how N addition affects global C storage by affecting the decomposition of organic matter. Our data suggest small increases in atmospheric N deposition could produce significant changes in communities of EM fungi and N and C cycles.