Bradyrhizobium sp. (Lupinus) in the winter rainfall region of South Africa

Widespread cultivation of lupin has resulted in the establishment of effective populations of Bradyrhizobium sp. (Lupinus) in the winter rainfall region of the Western Cape, South Africa. To determine whether inoculation increased yields of Lupinus angustifolius L., field trials were carried out at five sites in this region. Populations ranged from 380 rhizobia g^-1 in a moderately alkaline (pH 7.6) soil to >5,000 rhizobia g^-1 in four moderately acid (pH 5.5-5.8) soils. Soil isolates were generally similar to the inoculant strain WU425 in nitrogen-fixing effectiveness but several were significantly less effective. Average effectiveness of isolates from certain soils differed significantly. Although inoculation failed to appreciably increase nodule occupancy by WU425 in acid soils containing high populations of rhizobia, nodule occupancy was increased to 98% in the low population alkaline soil. The latter site was later abandoned because of disease. At the other sites, analysis of seed dry mass and protein content showed that yields were not significantly increased by either inoculation, nitrogen fertiliser (45 kg N ha^-1) or molybdenum applications. Analysis of genomic DNA by PCR fingerprinting showed that WU425 (isolated in Western Australia) and serologically related strains from other cultures clustered separately from the soil isolates. Isolates from the four acid soils were genomically diverse, whereas isolates from the alkaline soil formed a homogeneous cluster. Further investigation is required to determine the benefit of inoculation in alkaline soils of the winter rainfall region of the Western Cape.     

Space plasma physics: electron flux intensity distributions observed in response to particle beam emissions

Modifications of the suprathermal electron population were observed by an electron spectrometer on Spacelab 1 during electron beam injections. The instrument covered its energy range (100 to 12,500 electron volts) and field of view ( approximately 2pi) with high energy, angle, and time resolution. The measurements demonstrate the presence of strong beam-plasma interactions during high-current modes of accelerator operations. Spacecraft charging could be studied as well as processes that accelerated electrons to more than four times the injection energy.     

Earth-Based Observations of the Galileo Probe Entry Site

Earth-based observations of Jupiter indicate that the Galileo probe probably entered Jupiter's atmosphere just inside a region that has less cloud cover and drier conditions than more than 99 percent of the rest of the planet. The visual appearance of the clouds at the site was generally dark at longer wavelengths. The tropospheric and stratospheric temperature fields have a strong longitudinal wave structure that is expected to manifest itself in the vertical temperature profile.     

Spectral analysis of tropospheric aerosol measurements obtained with a new fast response sensor

A new fast response sensor was used in aircraft studies of fluctuations in the size distributions of tropospheric aerosol and their relation to fluctuations of trace gas concentrations and light scattering coefficients. Spectral analysis of data upwind of Buffalo, New York, and Houston, Texas, suggests important roles for atmospheric turbulence and chemical reaction in aerosol fluctuations.     

Electron Microscope Autoradiography of Bacteria Labeled with Iodine-125

The low-energy extranuclear electrons emitted by iodine-125 can be used for electron microscope autoradiography with results comparable to those obtained with tritium. Autoradiographs of tritium-labeled bacteria showed that 71 percent of all reacted grains localized on the cell. This figure was 86 percent when I(125)-labeled bacteria were used.     

Application of stable carbon isotope analysis to the detection of testosterone administration to cattle

The use of anabolic substances is prohibited in food-producing animals throughout the European Union. No method is available to reliably detect the misuse of natural hormones in cattle. A method was developed to detect the abuse of testosterone in cattle fattening. Synthesized testosterone is rather depleted in the (13)C/(12)C ratio. Hence, the method is based on gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis of urine. To select testosterone metabolites and endogenous reference compounds (ERC), the concentration of urinary steroids of cattle was investigated. Dehydroepiandrosterone and androst-5ene-3beta,17alpha-diol were chosen as ERCs to show endogenous (13)C/(12)C ratios. Etiocholanolone and 5alpha-androstane-3beta,17alpha-diol were chosen as the most important testosterone metabolites. Other metabolites known from literature like epitestosterone were less promising. In principle, GC/C/IRMS is a nonspecific method because finally carbon dioxide is analyzed. Therefore, a dedicated cleanup procedure for the selected steroids was developed. By means of proposed confidence intervals in the isotopic composition of ERCs and metabolites, the administration of testosterone to cattle could be detected reliably. Differences of up to 11 per thousand on the delta-scale between ERC and testosterone metabolites were found after testosterone administration, whereas endogenous differences did not exceed 2 per thousand.     

The invasive alien plant, <Emphasis Type="Italic">Impatiens glandulifera</Emphasis> (Himalayan Balsam), and increased soil erosion: causation or association? Case studies from a river system in Switzerland and the UK

Purpose

A monitoring investigation undertaken along the River Ibach, northwest Switzerland over the winter 2012/2013, found that riparian areas recently supporting the invasive plant Himalayan Balsam (HB) recorded significantly higher erosion rates than nearby uninvaded areas. This communication sythesises the latest findings about the influence of HB on sedimentation processes, again, from the Ibach, but also from a second river system in southwest UK.

Materials and methods

Erosion pins, a micro-profile bridge and a digital caliper were used to measure changes in soil surface profile (SSP) at selected riparian areas supporting HB plants along both rivers. Values were statistically compared against equivalent data recorded from nearby reference areas supporting mixed perennial vegetation. A comparison of source and sediment geochemistry was also undertaken on soil from HB-invaded and uninvaded floodplain areas along the Ibach, to assess the potential for identifying the extent to which either group acts as a sediment source.

Results and discussion

Erosion pin data indicate that soil loss from HB-colonised areas was significantly greater than soil loss from reference areas in two out of the four periods at the River Ibach site, and in two out of three measurement periods at the River Taw site. Colonisation of new HB sites may initially occur by hydrochorous processes, but HB plants may increase colonisation potential by trapping additional fine sediment and organic matter, including viable HB seeds. Geochemical results from the Ibach suggest that high inputs of suspended sediment originate from sources close to the river channel, but HB-invaded floodplain sources have geochemical properties that are most similar to suspended river sediment.

Conclusions

The findings from both rivers led us to rethink our original hypothesis; that HB promotes soil erosion, to an amended hypothesis in which HB may be associated with areas where high erosion is sometimes recorded. Whilst initial colonisation may be due to hydrochorous processes, as HB becomes increasingly established, the displacement of perennial vegetation increases the risk of erosion during the winter period when live HB plants are absent. Preliminary geochemical findings of floodplain soils supporting different vegetation types along the Ibach tentatively suggest that at least some material originating from HB sites may enter the watercourse.

     

PrPSc spreading patterns in the brain of sheep linked to different prion types

ABSTRACT: Scrapie in sheep and goats has been known for more than 250 years and belongs nowadays to the so-called prion diseases that also include e.g. bovine spongiform encephalopathy in cattle (BSE) and Creutzfeldt-Jakob disease in humans. According to the prion hypothesis, the pathological isoform (PrPSc) of the cellular prion protein (PrPc) comprises the essential, if not exclusive, component of the transmissible agent. Currently, two types of scrapie disease are known - classical and atypical/Nor98 scrapie. In the present study we examine 24 cases of classical and 25 cases of atypical/Nor98 scrapie with the sensitive PET blot method and validate the results with conventional immunohistochemistry. The sequential detection of PrPSc aggregates in the CNS of classical scrapie sheep implies that after neuroinvasion a spread from spinal cord and obex to the cerebellum, diencephalon and frontal cortex via the rostral brainstem takes place. We categorize the spread of PrPSc into four stages: the CNS entry stage, the brainstem stage, the cruciate sulcus stage and finally the basal ganglia stage. Such a sequential development of PrPSc was not detectable upon analysis of the present atypical/Nor98 scrapie cases. PrPSc distribution in one case of atypical/Nor98 scrapie in a presumably early disease phase suggests that the spread of PrPSc aggregates starts in the di- or telencephalon. In addition to the spontaneous generation of PrPSc, an uptake of the infectious agent into the brain, that bypasses the brainstem and starts its accumulation in the thalamus, needs to be taken into consideration for atypical/Nor98 scrapie.     

Characterization of Functional Properties of Gluten Proteins in Spelt Cultivars Using Rheological and Quality Factor Measurements

Wet glutens of 27 European spelt (Triticum aestivum ssp. spelta (L.) Thell.) cultivars were examined using fundamental rheological methods (oscillatory and creep tests) in conjunction with the determination of moisture contents of these glutens and the wet gluten contents of the flours. Furthermore, SDS sedimentation volumes were determined. A special baking test for spelt was developed that encompassed the characteristic elements used in the production of traditional German spelt speciality breads. Various significant correlations between gluten properties and baking results were found for three sets of spelt cultivars obtained from different demographic locations and years of harvest. Furthermore, the relationship between baking results (response) and gluten properties (predictors) could be modeled quite well with the help of multiple linear regression analysis. Radar charts used to profile the gluten properties of a particular cultivar showed a great amount of diversity within the spelt material, but there were also similarities between several cultivars. The differences between spelt cultivars should be taken into account when characterizing spelt in general terms or when comparing spelt and modern wheat.