Lupine induced "crooked calf disease" in Washington and Oregon: identification of the alkaloid profiles in Lupinus sulfureus, Lupinus leucophyllus, and Lupinus sericeus

Several lupines (Lupinus spp.) present on western U.S. rangelands contain alkaloids that are teratogenic to livestock and cause congenital birth defects in calves (crooked calf disease). Periodically, large losses of calves due to lupine-induced "crooked calf disease" occur in northern Oregon and eastern Washington state. Five lupine populations from this area representing three species (L. leucophyllus, L. sulfureus, and L. sericeus) were evaluated taxonomically and by gas chromatography/mass spectrometry, and the major alkaloids in each lupine species were identified. The teratogenic alkaloid anagyrine was present in both of the lupine species responsible for the high outbreaks in east-central Washington and northeastern Oregon. However, the alkaloid profiles of the two lupines identified as L. leucophyllus were dissimilar, as were the alkaloid profiles of the two lupines identified as L. sulfureus. Botanical classification is not sufficient to determine potential teratogenicity, and it must be followed by chemical characterization to determine risk to livestock.     

Evaluation of drying methods and toxicity of rayless goldenrod ( Isocoma pluriflora ) and white snakeroot ( Ageratina altissima ) in goats

White snakeroot and rayless goldenrod cause "trembles" and "milk sickness" in livestock and humans, respectively. The toxin in white snakeroot and rayless goldenrod was identified in 1927 and 1930, respectively, as tremetol. It was reported that the toxin in white snakeroot disappears as it is dried and that completely dried plants were incapable of producing trembles or milk sickness. Conversely, it has been reported that the rayless goldenrod toxin was not destroyed by drying and that the plant is toxic either fresh or dry. In this study the concentrations of tremetone, dehydrotremetone, and structurally similar compounds were determined in white snakeroot and rayless goldenrod before and after various drying conditions. Tremetone, dehydrotremetone, and structurally similar compounds in rayless goldenrod and white snakeroot are most stable upon freeze-drying, followed by air-drying, and least stable upon oven-drying (60 °C). Also demonstrated is that tremetone is stable and that dried white snakeroot and rayless goldenrod are capable of inducing toxicosis in livestock.     

Influence of seed endophyte amounts on swainsonine concentrations in astragalus and oxytropis locoweeds

Locoism is a toxic syndrome of livestock caused by the ingestion of a subset of legumes known as locoweeds endemic to arid and semiarid regions of the western United States. Locoweeds contain the toxic alkaloid swainsonine, which is produced by the endophytic fungi Undifilum species. Two chemotypes of plants can coexist within toxic populations of locoweeds: chemotype 1 plants are defined as individuals containing swainsonine concentrations greater than 0.01% and quantitatively greater amounts of Undifilum, while chemotype 2 plants are defined as individuals containing less than 0.01% swainsonine and quantitatively smaller amounts of Undifilum. To elucidate the mechanisms that govern chemotypes, the amount of Undifilum in seeds/embryos was manipulated, thus altering subsequent swainsonine concentrations in three locoweed species: Astragalus mollissimus, Astragalus lentiginosus, and Oxytropis sericea. Chemotype 1 seeds that were fungicide-treated or had the seed coat removed resulted in plants with swainsonine concentrations comparable to those in chemotype 2 plants. Conversely, embryos from seeds of chemotypes 1 and 2 that were inoculated with the endophyte resulted in plants with swainsonine concentrations comparable to those of chemotype 1 plants. This reproducible interconversion between the two swainsonine chemotypes suggests that the quantity of endophyte present in the seed at the time of germination is a key determinant of the eventual chemotype. Additionally, this is the first report of the inoculation of locoweeds with the endophyte Undifilum species.     

Development of a forest certification standard compatible with PEFC and FSC's management requirements. A case study from Greece

Greece currently has no national forest certification standard.This paper explains how a draft forest management standard forGreece was developed to be compatible with both the Forest StewardshipCouncil and the Programme for the Endorsement of Forest Certificationschemes requirements. The draft standard was tested in two contrastingforest areas to investigate its ease of operation, to indicatenecessary refinements to the standard and to reveal major areasof weakness in current forest management practices. Field testingshowed that the standard was operationally efficient and thatrelatively few changes to the standard were necessary. Majorweaknesses in current management practices were identified asbreaches of health and safety, poor training of forest workersand inadequate consultation with stakeholders.     

Resistance to amitraz in the parasitic honey bee mite Varroa destructor is associated with mutations in the β-adrenergic-like octopamine receptor

Varroa destructor is considered a major reason for high loss rate of Western honey bee (Apis mellifera) colonies. To prevent colony losses caused by V. destructor, it is necessary to actively manage the mite population. Beekeepers, particularly commercial beekeepers, have few alternative treatments other than synthetic acaricides to control the parasite, resulting in intensive treatment regimens that led to the evolution of resistance in mite populations. To investigate the mechanism of the resistance to amitraz detected in V. destructor mites from French and U.S. apiaries, we identified and characterized octopamine and tyramine receptors (the known targets of amitraz) in this species. The comparison of sequences obtained from mites collected from different apiaries with different treatment regimens, showed that the amino acid substitutions N87S or Y215H in the OctβR were associated with treatment failures reported in French or U.S. apiaries, respectively. Based on our findings, we have developed and tested two high throughput diagnostic assays based on TaqMan technology able to accurately detect mites carrying the mutations in this receptor. This valuable information may be of help for beekeepers when selecting the most suitable acaricide to manage V. destructor.

     

Contributions of woody and herbaceous vegetation to tropical savanna ecosystem productivity: a quasi-global estimate

To estimate the relative contributions of woody and herbaceous vegetation to savanna productivity, we measured the 13C/12C isotopic ratios of leaves from trees, shrubs, grasses and the surface soil carbon pool for 22 savannas in Australia, Brazil and Ghana covering the full savanna spectrum ranging from almost pure grassland to closed woodlands on all three continents. All trees and shrubs sampled were of the C3 pathway and all grasses of the C4 pathway with the exception of Echinolaena inflexa (Poir.) Chase, a common C3 grass of the Brazilian cerrado. By comparing the carbon isotopic compositions of the plant and carbon pools, a simple model relating soil delta 13C to the relative abundances of trees + shrubs (woody plants) and grasses was developed. The model suggests that the relative proportions of a savanna ecosystem's total foliar projected cover attributable to grasses versus woody plants is a simple and reliable index of the relative contributions of grasses and woody plants to savanna net productivity. Model calibrations against woody tree canopy cover made it possible to estimate the proportion of savanna productivity in the major regions of the world attributable to trees + shrubs and grasses from ground-based observational maps of savanna woodiness. Overall, it was estimated that 59% of the net primary productivity (Np) of tropical savannas is attributable to C4 grasses, but that this proportion varies significantly within and between regions. The C4 grasses make their greatest relative contribution to savanna Np in the Neotropics, whereas in African regions, a greater proportion of savanna Np is attributable to woody plants. The relative contribution of C4 grasses in Australian savannas is intermediate between those in the Neotropics and Africa. These differences can be broadly ascribed to large scale differences in soil fertility and rainfall.     

Adipsin: a circulating serine protease homolog secreted by adipose tissue and sciatic nerve

Adipsin is a serine protease homolog whose primary structure was predicted from the nucleotide sequence of a differentiation-dependent adipocyte messenger RNA. Immunoblots probed with antisera to synthetic peptides identify two forms of adipsin that are synthesized and secreted by 3T3 adipocytes. These proteins of 44 and 37 kilodaltons are converted to 25.5 kilodaltons by enzymatic deglycosylation. Although adipsin is principally synthesized in adipose tissue, it is also produced by sciatic nerve and is found in the bloodstream. Because of the apparent restriction of adipsin synthesis to tissues highly active in lipid metabolism, its presence in serum, and its modulation in altered metabolic states, this molecule may play a previously unrecognized role in systemic lipid metabolism or energy balance.     

Effects of dietary energy source and level and injection of tilmicosin phosphate on immune function in lipopolysaccharide-challenged beef steers

Twenty-four Angus x Hereford crossbred steers (247 kg BW; SE = 2.4 kg) were used in a completely random design to evaluate the effect of energy source and level with or without antibiotic administration on measures of immune function. Steers were fed 1 of 3 dietary treatments: a 70% concentrate diet ad libitum (70AL), a 30% concentrate diet ad libitum (30AL), and a 70% concentrate diet offered in an amount calculated to provide NE(g) intake equal to the 30AL treatment (70RES). Half the steers in each dietary treatment received a s.c. injection of tilmicosin phosphate (ANTI; 1 mL/30 kg of BW); the other half received an equal volume of saline s.c. (SAL). Steers were offered the treatment diets for 28 d before and were administered the ANTI or SAL injections 2 d before indwelling catheters were placed in the jugular vein and 2.0 microg/kg of BW of Escherichia coli lipopolysaccharide (LPS) was administered i.v. Blood serum was collected at 30-min intervals from -2 to 6 h and at 8, 12, 24, 48, and 72 h relative to the LPS challenge. Increased energy intake (70AL) increased (P < or = 0.04) DMI, ADG, and rectal temperature (RT) after the challenge compared with the 70RES treatment. The 30AL treatment increased the maximum concentrations and area under the response curve of the proinflammatory cytokines (PIC) interferon-gamma, tumor necrosis factor-alpha, and IL-6 (P < or = 0.05) compared with the average of the 70AL and 70RES treatments. Decreased energy intake (70RES vs. 70AL) increased IL-6 (P < or = 0.003) but did not significantly increase interferon-gamma and tumor necrosis factor-alpha (P > or = 0.14) after LPS administration. Tilmicosin administration decreased the time to attain maximal RT (P = 0.01) by 1 h without altering the peak RT (P = 0.85), and tilmicosin interacted with energy intake to increase prechallenge PIC in 70RES vs. 70AL (P < or = 0.05). Results indicate that increased PIC response, presumably resulting from a combination of decreased energy intake and from direct effects of roughage, may be a mode of action for the slight decrease in morbidity that often occurs when newly received, stressed calves are fed roughage-based receiving diets. Tilmicosin phosphate might have immunomodulatory capacity beyond its direct effects on pathogenic bacteria, and these effects could interact with dietary energy intake in cattle.     

Mode of action of thiocyanates and iodides in aminotriazole formulations

Ammonium thiocyanate ( I ) was shown to inhibit the oxidation of aminotriazole (3-amino-1,2,4-triazole) in two free-radical generating systems: (a) riboflavin photo-sensitised oxidation; and (b) oxidation by hydroxyl radicals. Evidence from in-vitro studies is presented to show that I could enhance aminotriazole performance by being preferentially oxidised within the leaf, thereby preventing aminotriazole free-radical formation and subsequent conjugation with amino acids and other compounds. This opens up the possibility of a whole new range of additives which could enhance translocation by inhibiting free-radical reactions. A comparison of possible inhibitors revealed that cyanides, iodides and perhaps bromides may be of use in this respect. In addition to inhibiting free-radical reactions, I and potassium iodide ( II ) were shown to have a considerable effect on the uptake of aminotriazole by bean leaves (Phaseolus vulgaris var. Canadian Wonder). In the absence of additives, uptake of aminotriazole was negligible (1.8%); in the presence of a 1:1 molar ratio of I or II , uptake of aminotriazole was increased to 36.6% and 54.2% respectively. At a 3:1 molar ratio of additive:aminotriazole, the respective figures were 63.5% and 81.0%. II appeared to be the more efficient of the two additives at higher humidity. However, the results and observations indicated that the situation may be reversed under low-humidity conditions.