The present paper reviews briefly the recent advance in radioanalysis of low level plutonium in environmental and biological samples. Lots of new radiochemical methods for determination of plutonium in aerosols, natural waters, soil, sediments and various biological materials have been developed. The use and prospects of several radiochemical procedures are discussed.
Authors:H. Bjørnstad, H. Lien, Yu-Fu Yu, and B. Salbu
Low level90Sr in environmental and biological samples is determined using a combined HDEHP solvent extraction-liquid scintillation procedure. Yttrium-90 is selectively extracted from nitric acid solution into 5% di(2-ethylhexyl) phosphoric acid (HDEHP) in toluene, and90Y in the organic phase is measured directly using an ultra low level liquid scintillation spectrometer.The working program of the Quantulus counter has been optimized. As the counting efficiency using liquid scintillation counting is high and the stripping and precipitation of Yttrium-90 oxalate is omitted, this procedure is simpler and more timesaving than traditional methods. The chemical recoveries of90Y were 85.1% for soil, 75.7% for milk and 65.3% for bone. The detection limit is 8 mBq.
Authors:Yu Yu-fu, B. Salbu, H. Bjørnstad, and H. Lien
An improvement of -energy resolution for determining low level plutonium has been investigated using combined solvent extraction-low level liquid scintillation counter. In the present work, -energy resolution of 270–290 keV for liquid scintillation spectra of236Pu and239Pu is attained. Thus the simultaneous determination of low level plutonium with -liquid scintillation spectrometry may be practized.
Authors:Y. Zhang, K. Ma, M. Anand, W. Ye, and B. Fu
Alpha, beta, and gamma diversity are three fundamental biodiversity components in ecology, but most studies focus only on the scale issues of the alpha or gamma diversity component. The beta diversity component, which incorporates both alpha and gamma diversity components, is ideal for studying scale issues of diversity. We explore the scale dependency of beta diversity and scale relationship, both theoretically as well as by application to actual data sets. Our results showed that a power law exists for beta diversity-area (spatial grain or spatial extent) relationships, and that the parameters of the power law are dependent on the grain and extent for which the data are defined. Coarse grain size generates a steeper slope (scaling exponent z) with lower values of intercept (c), while a larger extent results in a reverse trend in both parameters. We also found that, for a given grain (with varying extent) or a given extent (with varying grain) the two parameters are themselves related by power laws. These findings are important because they are the first to simultaneously relate the various components of scale and diversity in a unified manner.
Authors:Z. Tang, S. Fu, Z. Ren, H. Zhang, Z. Yang, and B. Yan
Wheat-rye 1BL.1RS translocations have been widely used in wheat breeding programs. A 1BL.1RS translocation wheat line, 91S-23, was developed from a 1R monosomic addition of the rye
inbred line L155 into wheat
MY11. A new commercial wheat cultivar, CN18, which also contained the 1BL.1RS translocation, was derived from the cross MY11 × 91S-23. Polymerase chain reaction (PCR) and fluorescence
hybridization (FISH) indicated that the rye centromere was eliminated from the 1BL.1RS chromosomes of CN18 but not from 91S-23. Based on the 1RS source and the centromeric structure of the translocation chromosome, CN18 qualifies as a new wheat cultivar possessing a 1BL.1RS translocation. CN18 displayed high yield performance and resistance to powdery mildew and stripe rust, whereas 91S-23 was susceptible to these diseases. The present study provides a new 1RS resource for wheat improvement.
Authors:Guodong Zheng, Bihong Fu, Yi Duan, Qi Wang, M. Matsuo, and B. Takano
Mesozoic-Cenozoic reddish and green beds are widely distributed in northwest China. Mössbauer spectroscopy revealed that the composition of iron species varies with color in the middle-upper Jurassic sedimentary rocks from the Turpan Basin. Three main kinds of iron species were identified: (1) ferric iron of hematite (hem-Fe3+), (2) paramagnetic ferric iron (para-Fe3+), and (3) paramagnetic ferrous iron (para-Fe2+). Pyrite iron (pyr-Fe2+) was revealed only in a few samples. In general, there is a direct correlation between rock color, iron species and total iron content, however, in detail, this relationship is more complicated. The reddish rocks contain higher contents of total iron and hem-Fe3+, whereas the gray rocks contain much more para-Fe2+. However, relatively low hematite content cannot give red color to rocks, probably due to suppression by other pigments such as organic matter in black or chlorite in green. The dark or green rocks normally contain either only paramagnetic Fe2+ and paramagnetic Fe3+ species or these two species associated with hematite Fe3+, but the relative content of hematite species is lower. The variations of different iron species control lithological properties such as color and also may reflect the sedimentary conditions. Moreover, iron speciation in these rocks is one of the main factors, which result the color features of rocks in remote sensing imagery.
Authors:V. Szott, B. Reichelt, T. Alter, A. Friese, and U. Roesler
Carvacrol, a primary constituent of plant essential oils (EOs), and its antimicrobial activity have been the subject of many in vitro studies. Due to an increasing demand for alternative antimicrobials and an emerging number of antibiotic resistant bacteria, the use of essential oils has played a major role in many recent approaches to reduce Campylobacter colonization in poultry before slaughter age. For that purpose, the reducing effect of carvacrol on Campylobacter jejuni prevalence in broilers was determined in vivo in an experimental broiler chicken model during an entire fattening period. Carvacrol was added to the feed in a concentration of 120 mg/kg feed four days post hatch until the end of the trial. In this study, we demonstrated a statistically significant decrease of C. jejuni counts by 1.17 decadic logarithm (log10) most probable number (MPN)/g in cloacal swabs during starter and grower periods (corresponding to a broilers age between 1 and 28 days). Similar results were observed for colon enumeration at the end of the trial where C. jejuni counts were significantly reduced by 1.25 log10 MPN/g. However, carvacrol did not successfully reduce Campylobacter cecal colonization in 33-day-old broilers.
Authors:Ting Fu, Eva B. Znalesniak, Thomas Kalinski, Luisa Möhle, Aindrila Biswas, Franz Salm, Ildiko Rita Dunay, and Werner Hoffmann
The peptide trefoil factor family 3 (TFF3) is a major constituent of the intestinal mucus, playing an important role in the repair of epithelial surfaces. To further understand the role of TFF3 in the protection of intestinal epithelium, we tested the influence of TFF3 in a murine Toxoplasma gondii-induced ileitis model. Surprisingly, TFF3KO mice showed a reduced immune response in the ileum when compared to wild-type animals. Interleukin-12 and interferon-γ expression levels as well as the number of CD4+ lymphocytes were reduced in the infected TFF3KO mice. These effects were in line with the trend of elevated parasite levels in the ileum. Moreover, TFF1 expression was upregulated in the spleen of infected mice. These initial results indicate that TFF3 is involved in the immune pathology of T. gondii infection-induced intestinal inflammation. Thus far, the mechanisms of how TFF3 influences the immune response are not fully understood. Further studies should identify if TFF3 affects mucus sensing of dendritic cells and how TFF3 is involved in regulating the immune response as an intrinsic secretory peptide of immune cells.
Premature termination codons (PTCs) are an important reason for the silence of highmolecular- weight glutenin subunits in Triticum species. Although the Glu-A1y gene is generally silent in common wheat, we here isolated an expressed Glu-A1y gene containing a PTC, named 1Ay8.3, from Triticum monococcum ssp. monococcum (AmAm, 2n = 2x = 14). Despite the presence of a PTC (TAG) at base pair positions 1879–1881 in the C-terminal coding region, this did not obviously affect 1Ay8.3 expression in seeds. This was demonstrated by the fact that when the PTC TAG of 1Ay8.3 was mutated to the CAG codon, the mutant in Escherichia coli bacterial cells expressed the same subunit as in the seeds. However, in E. coli, 1Ay8.3 containing the PTC expressed a truncated protein with faster electrophoretic mobility than that in seeds, suggesting that PTC translation termination suppression probably occurs in vivo (seeds) but not in vitro (E. coli). This may represent one of only a few reports on the PTC termination suppression phenomenon in genes.