The Relationship between Structurally Different Pyrrolizidine Alkaloids and Western Flower Thrips Resistance in F2 Hybrids of Jacobaea vulgaros and Jacobaea aquatica

Segregating plant hybrids often have more ecological and molecular variability compared to parental species, and are therefore useful for studying relationships between different traits, and the adaptive significance of trait variation. Hybrid systems have been used to study the relationship between the expression of plant defense compounds and herbivore susceptibility. We conducted a western flower thrips (WFT) bioassay using a hybrid family and investigated the relationship between WFT resistance and pyrrolizidine alkaloid (PA) variation. The hybrid family consisted of two parental (Jacobaea vulgaris and Jacobaea aquatica) genotypes, two F1 genotypes, and 94 F2 hybrid lines. The J. aquatica genotype was more susceptible to thrips attack than the J. vulgaris genotype, the two F1 hybrids were as susceptible as J. aquatica, and susceptibility to WFT differed among F2 hybrid lines: 69 F2 lines were equally susceptible compared to J. aquatica, 10 F2 lines were more susceptible than J. aquatica and 15 F2 lines were as resistant as J. vulgaris or were intermediate to the two parental genotypes. Among 37 individual PAs that were derived from four structural groups (senecionine-, jacobine-, erucifoline- and otosenine-like PAs), the N-oxides of jacobine, jaconine, and jacoline were negatively correlated with feeding damage caused by WFT, and the tertiary amines of jacobine, jaconine, jacoline, and other PAs did not relate to feeding damage. Total PA concentration was negatively correlated with feeding damage. Among the four PA groups, only the total concentration of the jacobine-like PAs was negatively correlated with feeding damage. Multiple regression tests suggested that jacobine-like PAs play a greater role in WFT resistance than PAs from other structural groups. We found no evidence for synergistic effects of different PAs on WFT resistance. The relationship between PA variation and WFT feeding damage in the Jacobaea hybrids suggests a role for PAs in resistance to generalist insects

Dutch survey pyrrolizidine alkaloids in animal forage

Pyrrolizidine alkaloids (PAs) are secondary plant metabolites produced by a number of plants from the Asteraceae (Compositae), Boriginaceae and Fabaceae (Leguminosae) families. Many of these alkaloids have been shown to be highly toxic, causing hepatic veno-occlusive disease (VOD), liver cirrhosis and ultimately death. PAs may have also mutagenic and carcinogenic potential. Amongst livestock, cattle and horses are especially susceptible to the toxic effects of the PAs. Humans may also be at risk by the consumption of milk of livestock fed with PA-contaminated forage. At RIKILT - Institute of Food Safety a (semi)quantitative method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of PAs in animal feeds has been developed and validated. This method comprises 40 macrocyclic PAs (including tertiary amines and N-oxides) representative for ragwort species. The method has been used for the analysis of 147 forage samples collected in 2006-2008

The cold gaseous halo of NGC 891

We present HI observations of the edge-on galaxy NGC 891. These are among the deepest ever performed on an external galaxy. They reveal a huge gaseous halo, much more extended than seen previously and containing almost 30 % of the HI. This HI halo shows structures on various scales. On one side, there is a filament extending (in projection) up to 22 kpc vertically from the disk. Small (M_HI ~ 10^6 Msol) halo clouds, some with forbidden (apparently counter-rotating) velocities, are also detected. The overall kinematics of the halo gas is characterized by differential rotation lagging with respect to that of the disk. The lag, more pronounced at small radii, increases with height from the plane. There is evidence that a significant fraction of the halo is due to a galactic fountain. Accretion from intergalactic space may also play a role in building up the halo and providing low angular momentum material needed to account for the observed rotation lag. The long HI filament and the counter-rotating clouds may be direct evidence of such accretion.Comment: Accepted for publication in The Astronomical Journal. High-resolution version available at http://www.astron.nl/~oosterlo/n891Pape

Estimating Shadow Wage Rates for Economic Project Appraisal

One of the central concerns in cost benefit analysis is the adjustment of distortions in markets to provide a better guide to a more effective allocation of scarce resources. The objectives of this paper are to develop a model for the estimation of the shadow wage rate (SWR) for groups of occupations and to estimate the SWRs for the major groups of occupations in Australia. The main findings of the analysis indicate that estimated SWRs for major groups of occupations are different from the corresponding market wage rates, and that estimated SWRs of the groups are different. The results of the study demonstrate the importance of estimation of the SWR as a part of the appraisal process of investment projects. The ratio analysis indicates the significance of the difference between SWR and market wage rate, which is recommended to be adjusted is economic analysis of projects.Wages, Shadow Prices, Economic Projects

Short-term effect of soil disturbance by mechanical weeding on plant available nutrients in an organic vs conventional rotations experiment

The question whether soil disturbance from mechanical weeding in organic systems affects nutrient release from organic matter in compost-amended soil was examined in a long-term organic-versus-conventional rotational cropping system experiment over three years. The experimental design included continuous snap beans, and a fully phased snap beans/fall rye crop rotation sequence. Treatments were combinations of yearly applied fertiliser (synthetic fertiliser, 1× compost, 3× compost) and weed control (herbicide, mechanical weeding). The 1× compost rate was calculated to deliver the equivalent of 50 kg N ha-1: equal to the rate ofN in the synthetic fertiliser treatments. Ion exchange membranes were buried for 24 hours following mechanical weeding in bean plots. Adsorbed ions were then eluted and quantified. Available ammonium-nitrogen was not affected byweeding treatment, but nitrate-nitrogen was consistently less in mechanically weeded plots than in plots treated with herbicide. Principal component analysis of NH4-N, NO3-N, P, K, Ca and Mg availabilities showed distinct groupings of treatments according to fertility treatment rather than weeding treatment. The effect of cropping sequence on available nutrients was pronounced (P ≤ 0.001) only in plots amended with synthetic fertilisers

Radial velocity variations of the pulsating subdwarf B star PG 1605+072

We present an analysis of high-speed spectroscopy of the pulsating subdwarf B star PG 1605+072. Periodic radial motions are detected at frequencies similar to those reported for photometric variations in the star, with amplitudes of up to 6 km/s. Differences between relative strengths for given frequency peaks for our velocity data and previously measured photometry are probably a result of shifting of power between modes over time. Small differences in the detected frequencies may also indicate mode-shifting. We report the detection of line-shape variations using the moments of the cross correlation function profiles. It may be possible to use the moments to identify the star's pulsation modes.Comment: 5 pages, 6 figure

Differential Effects of Neonatal Testosterone Treatment on Aggression in Two Selection Lines of Mice

Selection lines of mice, artificially selected for aggression based upon the attack latency score (ALS), were used. In order to determine the relative contribution of neonatal testosterone (T) in the development of aggression, we vary the plasma-T level in males of both selection lines on the day of birth. At 14 weeks the ALS was measured. Neonatal T treatment results in a reduction of aggression in the long attack latency (LAL) line, whereas aggressive behaviour of the short attack latency (SAL) line is not affected. Both selection lines show reduction in testicular weight, although the total amount of T-producing Leydig cells was not affected. Neonatal T may cause a permanent reduction in aggressive behaviour in the LAL line only, probably due to differential appearance of critical periods. It is suggested that the difference in aggressive behaviour between SAL and LAL selection lines is due to a prenatally determined difference in neonatal T sensitivity of the brain.

Research on Operational Characteristics of Imported Rails under Conditions of East Siberian Railway

In world's manufacturing of railroad rails there are several thermal bonding methods: differentiated waterflow quenching, air-blast or spray quenching, rail head's hardening in polymer solution and bulk oil hardening; rails' service durability is strongly dependent on thermo-hardening methods. Until recently, all of rails, produced at Nizhniy Tagil and Kuznetsk Metallurgical Works, were subjected to bulk oil hardening. Only in 2010-2011, in the Russian Federation, differentiated air quenching of rails was started at the JSC "EVRAZ ZSMK"; and rail heads' hardening in polymer solution - at the JSC "Mechel". At the same time, exploitation of imported rails with differentiated hardening has been performed on Russian railways since 1995. Service durability of these rails in Siberia and the Far North is of considerable interest. In this paper we investigated the quality of P65-type rails, made in Japan, removed after use from curved track section of the East-Siberian railway

Differences in Yield Parameters of Emmer in Comparison with Old and New Varieties of Bread Wheat

Emmer wheat (Triticum diccocum Schrank) belonged to the most frequent species of cereals in the past. Nowadays, it is grown in arid and montane areas in particular. Interest in this cereal species has increased, as it is tolerant to biotic and abiotic stressing factors. Therefore, yield parameters were evaluated in three-year (2007, 2008 and 2010) trials that were carried out in two different localities in the Czech Republic. Results of the research were compared to characteristics of four old and two top modern bread wheat (Triticum aestivum L.) cultivars. The emmer wheat varieties were resistant to usual wheat diseases. They formed their yield by a quantity of productive tillers (2.5), whereas the varieties of bread wheat had less productive tillers (1.5) per one plant. The distribution of assimilates was worse in the emmer wheat plants and it provoked a lower harvest index (0.33) there. Grain yield of the emmer wheat varieties reached 58% of the yield level of the mean of control bread wheat varieties. High crude protein content in grain (17.91%) was an advantage of the emmer wheat varieties; the control bread wheat varieties reached 13.73%. Protein content was positively influenced (P < 0.01) by an ability of the emmer varieties to uptake as much nitrogen as possible from the soil during the flowering period. Adaptability to the land and climatic environmental conditions was another positive characteristic of the emmer wheat landraces in comparison with old and modern bread wheat varieties