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Abundant Quantities (abundant + quantity)
Selected AbstractsMillennia-long tree-ring records from Tasmania and New Zealand: a basis for modelling climate variability and forcing, past, present and future,JOURNAL OF QUATERNARY SCIENCE, Issue 7 2006Edward R. Cook Abstract Progress in the development of millennia-long tree-ring chronologies from Australia and New Zealand is reviewed from the perspective of modelling long-term climate variability there. Three tree species have proved successful in this regard: Huon pine (Lagarostrobos franklinii) from Tasmania, silver pine (L. colensoi) from the South Island of New Zealand, and kauri (Agathis australis) from the North Island of New Zealand. Each of these species is very long-lived and produces abundant quantities of well-preserved wood for extending their tree-ring chronologies back several millennia into the past. The growth patterns on these chronologies strongly correlate with both local and regional warm-season temperature changes over significant areas of the Southern Hemisphere (especially Huon and silver pine) and to ENSO variability emanating from the equatorial Pacific region (especially kauri). In addition, there is evidence for significant, band-limited, multi-decadal and centennial timescale variability in the warm-season temperature reconstruction based on Huon pine tree rings that may be related to slowly varying changes in ocean circulation dynamics in the southern Indian Ocean. This suggests the possibility of long-term climate predictability there. Copyright © 2006 John Wiley & Sons, Ltd. [source] Resistance to chytridiomycosis varies among amphibian species and is correlated with skin peptide defensesANIMAL CONSERVATION, Issue 4 2007D. C. Woodhams Abstract Innate immune mechanisms of defense are especially important to ectothermic vertebrates in which adaptive immune responses may be slow to develop. One innate defense in amphibian skin is the release of abundant quantities of antimicrobial peptides. Chytridiomycosis is an emerging infectious disease of amphibians caused by the skin fungus, Batrachochytrium dendrobatidis. Susceptibility to chytridiomycosis varies among species, and mechanisms of disease resistance are not well understood. Previously, we have shown that Australian and Panamanian amphibian species that possess skin peptides that effectively inhibit the growth of B. dendrobatidis in vitro tend to survive better in the wild or are predicted to survive the first encounter with this lethal pathogen. For most species, it has been difficult to experimentally infect individuals with B. dendrobatidis and directly evaluate both survival and antimicrobial peptide defenses. Here, we demonstrate differences in susceptibility to chytridiomycosis among four Australian species (Litoria caerulea, Litoria chloris, Mixophyes fasciolatus and Limnodynastes tasmaniensis) after experimental infection with B. dendrobatidis, and show that the survival rate increases with the in vitro effectiveness of the skin peptides. We also observed that circulating granulocyte, but not lymphocyte, counts differed between infected and uninfected Lit. chloris. This suggests that innate granulocyte defenses may be activated by pathogen exposure. Taken together, our data suggest that multiple innate defense mechanisms are involved in resistance to chytridiomycosis, and the efficacy of these defenses varies by amphibian species. [source] Separation of Pure and Immunoreactive Virus-Like Particles Using Gel Filtration Chromatography Following Immobilized Metal Ion Affinity ChromatographyBIOTECHNOLOGY PROGRESS, Issue 2 2001Yu-Shen Cheng A purification process was developed to obtain highly pure rVP2H particles, formed by a structural protein (VP2) of the infectious bursal disease virus (IBDV) with six additional histidine residues at its C-terminus. The ultimate goal was the development of an efficient subunit vaccine against IBDV infection. The particles within the infected High-Five (Hi-5) cell lysates were partially purified by employing immobilized metal ion (Ni2+) affinity chromatography (IMAC). The initial step could recover approximately 85% of immunoreactive rVP2H proteins but failed to separate the rVP2H particles from the free rVP2H proteins or its degraded products. To separate the particulate form from the free form of rVP2H, an additional step was added, which used either gel filtration chromatography or CsCl density gradient ultracentrifugation. Both were able to produce extremely pure rVP2H particles with a buoyant density close to 1.27 g/cm3. However, the former method can process a larger sample volume than does the latter. By integrating IMAC and gel filtration chromatography, 1 mg of extremely pure rVP2H particles was routinely obtained from a 500 mL Hi-5 cell culture broth. The separation of the particulate form from the free form of rVP2H proteins exposes their respective immunogenicity to induce the virus-neutralizing antibodies and the ability to protect chickens from IBDV infection. Additionally, the abundant quantities of pure rVP2H particles coupled with their uniform dimensions facilitates an understanding of higher order structure of the immunogenic particles and can therefore result in improved vaccines against the virus. [source] Variations of chemical compositions in coarse aerosols and fine aerosols in two successive episodesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2006Chung-Yih Kuo Abstract Particulate matter with diameters less than 2.5 ,m (PM2.5) and ranging between 10 to 2.5 ,m (PM10-2.5) were simultaneously collected at four air-quality monitoring stations in the Taichung area of central Taiwan during the period of February 12 to 22, 2004. Two different types of PM10 episodes, a nonlocal dust-storm episode and a local episode, were observed in the present study. High concentrations of coarse aerosols occurred during the dust-storm episode, whereas high concentrations of fine aerosols were present during the local episode. Relatively high levels of Na+, Mg2+, Ca2+, and Cl, in coarse aerosols were observed during the dust-storm episode. Very high concentrations of secondary aerosols (NH+4, SO2,4, and NO,3) in fine aerosols were observed during the local episode. The nitrate ion demonstrated the greatest increase in the ratios of ionic species to PM2.5 and ionic species to PM10-2.5 during the local episode. Significantly high ratios (0.444) of NO,3 to NO2 in fine aerosols were present during the local episode, indicating that the relatively high formation rate of NO,3 was one of the important factors leading to the increase of the NO,3 to PM2.5 ratio during the local episode. Results also showed that an abundant quantity of fine ammonium nitrate was formed during the local episode, and chloride depletion probably was the major pathway to form coarse NaNO3 during this episode. [source] AN UNUSUAL POLYUNSATURATED C-27 HYDROCARBON FROM THE MARINE DINOFLAGELLATE PYROCYSTIS LUNULAJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Leblond, J. D.1 & Chapman, P. J.2 1Department of Biology, Middle Tennessee State University, Murfreesboro, TN 37132. 2US EPA (NHEERL), Gulf Ecology Division, 1 Sabine Island Dr., Gulf Breeze, FL 32561 Studies of the lipids of different algal species have revealed a diversity of fatty acids, sterols, and hydrocarbons, of which several are considered useful biomarkers, with potential for characterizing phytoplankton community composition. To extend this approach and characterize the lipids and lipid classes of laboratory-cultured marine dinoflagellates, a silicic acid fractionation system was developed to obtain compositional data for sterols and hydrocarbons of over forty species. In the course of this work, a neutral fraction obtained from a lipid extract of Pyrocystis lunula was found to contain an abundant quantity of a long-chain polyunsaturated hydrocarbon, along with previously reported keto-steranes. The hydrocarbon molecular weight (364) and retention time obtained by gas chromatography/mass spectrometry analysis suggested a C27 compound, which was confirmed by reduction (Adams catalyst) to give the straight chain alkane, n-heptacosane. The presence of eight double bonds was established by deuteration to give a product with molecular weight 396. While the positions of double bonds have not been established, the carbon number of this hydrocarbon and the number of double bonds strongly suggest formation by decarboxylation of the recently described, long-chain polyunsaturated C28 fatty acid shown to be a constituent of phospholipids. This hydrocarbon was not found in any other genus of the examined dinoflagellates, and appears to be one of the first identifications of a hydrocarbon in this class of algae. The function(s) of this compound in P. lunula is currently unclear. [source] | ||||||||||