Volatile metabolites from actinomycetes

Twenty-six Streptomyces spp. were screened for their volatile production capacity on yeast starch agar. The volatile organic compounds (VOCs) were concentrated on a porous polymer throughout an 8-day growth period. VOCs were analyzed by gas chromatography with flame ionization detection and identified or characterized by gas chromatography-mass spectrometry. A total of 120 VOCs were characterized by retention index and mass spectra. Fifty-three compounds were characterized as terpenoid compounds, among which 18 could be identified. Among the VOCs were alkanes, alkenes, alcohols, esters, ketones, sulfur compounds, and isoprenoid compounds. Among the most frequently produced compounds were isoprene, acetone, 1-butanol, 2-methyl-1-propanol, 3-methyl-3-buten-1-ol, 3-methyl-1-butanol, 2-methyl-1-butanol, cyclopentanone, dimethyl disulfide, dimethyl trisulfide, 2-phenylethanol, and geosmin. The relationship between the excretion of geosmin and the production of spores was examined for one isolate. A good correlation between headspace geosmin and the number of spores was observed, suggesting that VOCs could be used to indicate the activity of these microorganisms in heterogeneous substrates.     

Effect of dietary nitrogen content on the urine metabolite profile of dairy cows assessed by nuclear magnetic resonance (NMR)-based metabolomics

NMR-based metabolomics was applied on urine samples from 32 cows that were fed four levels of crude protein (124, 135, 151, and 166 g/kg DM, respectively) in a crossover design with the aim of identifying urinary metabolites related to nitrogen intake and nitrogen efficiency. Principal component analysis (PCA) on selected regions of the obtained (1)H NMR spectra revealed an effect of crude protein intake on NMR signals in the 0.5-3.0 and 5.0-10.0 ppm regions. Partial least-squares (PLS) regressions confirmed a correlation between the NMR metabolite profile and both nitrogen intake and efficiency. The NMR signals that correlated with nitrogen intake and efficiency included urea, hippurate, phenylacetylglutamine, and p-cresol sulfate, which all contributed to the prediction of nitrogen intake and efficiency. Thus, it was not possible to identify a single metabolite that could be used as a marker to predict nitrogen efficiency, and it can be concluded that a wide-ranging urinary metabolite profile is needed to evaluate nitrogen efficiency in ruminants.     

Piglet performance and physiological effects linked to reduced glucosinolate transformations in feed products based on rapeseed pressed cakes

The nutritional quality of rapeseed press cakes (RPCs) in piglet feed is closely linked to its digestibility and the content of glucosinolates. This study investigates the significance of intact glucosinolate (glc) levels and degree of glc transformations on piglets performance. Four different RPCs were made from a low glc (11 µmol/g seed DM) containing B. napus L. seed variety Lioness (RPC‐LW, RPC‐LXW, RPC‐LC, RPC‐LCD). RPC made from the variety Excalibur containing the upper level of glc (24 µmol/g seed DM) of double rapeseed and produced at higher and prolonged temperature (RPC‐UXW) served as negative control, while soya bean protein concentrate served as positive control. Piglets (8 kg) were fed ad libitum diets balanced for RPC protein content, with RPC inclusion of 84–98 g/kg (day 0–14) and 151–178 g/kg (day 15–50). Glc transformation was reduced from 42% to 24% (7.3–4.2 µmol/g RPC) when the temperature input was lowered in the warm pressing of oil, while the glc loss was less pronounced (17%) when cold pressing was applied. The following feed pelleting process further reduced Glc concentration from 11% to 40% in warm‐pressed RPCs and 54 to 85% in cold‐pressed RPCs. The RPC products replaced soya bean protein without any negative effects on performance, except for piglets served cold‐pressed RPC, which had a reduction in average daily weight gain (ADG) (5%–7%, p < 0.05, Day 15–50). RPC in the feed led to increased liver weight in all piglets (p = 0.026). This may point at long‐term effects from feeding with RPC. Intestinal absorption of intact glcs was proven by their detection in urine. In conclusion, warm‐pressed RPC can be used as feed for piglet, while the presence of active myrosinase may have a negative effect on performance and cakes should either be included in lower amounts than used in the present study (18%) or include myrosinase inactivation before use.     

Screening for intrinsic water use efficiency in a potato dihaploid mapping population under progressive drought conditions

A drought screening experiment focusing on intrinsic water use efficiency (WUE_i) was carried out among 132 clones belonging to a dihaploid potato mapping population. The clones were exposed to progressive soil drying during a five-day period in a greenhouse pot experiment. Analysis of the underlying variables was done based on a multivariate data analysis strategy. The strategy successfully divided the clones into WUE_i performance categories. Differences between clonal WUE_i responses were traced back to differences in the net photosynthetic rate. Stomatal conductance (g_s) did not vary significantly between the clones. Leaf abscisic acid (ABA) concentration and leaf water potential were found to reflect known isohydric behaviour for potato, and a non-linear relationship could be established for g_s and leaf ABA concentration across the WUE_i groups. Similarly, a common non-linear relationship between leaf ABA concentration and soil water potential was found. The latter findings suggest that the investigated population did not harbour significant genetic variation as to ABA production as function of soil desiccation level or with respect to the sensitivity of stomatal aperture vis-à-vis leaf ABA concentration and soil water potential.     

Binding of recombinant norovirus like particle to histo-blood group antigen on cells in the lumen of pig duodenum

Histo-blood group antigens (HBGA) expressed on cells in the human GI tract have been shown to function as receptors for noroviruses. In concordance with earlier reports (Backer et al., 1997; Yamamoto and Yamamoto, 2001), this study found that individual pigs are either HBGA type A positive or type H1 (type O) positive. Recombinant norovirus like particles from a genogroup I (rNVLP) or three genogroup II (rMOH, rVA207, and rVA387) strains bound to plates coated with pig gastro-intestinal washings with similar binding patterns to humans. The binding of human norovirus like particles was inhibited by pre-incubating the wells with MAbs specific for either type A or type H1 HBGA, or by the presence of free HBGAs from human saliva. Co-localization of rNVLP and corresponding HBGA on epithelial cells of pig gastro-intestinal tissue (PGIT) was also observed. These findings suggest that rNVLP binds to HBGAs expressed on PGIT epithelial cells. This is the first report of the specific binding of human rNVLP to HBGAs in epithelial cells of pig gastrointestinal tissue. It highlights the importance of further study of human norovirus incidence and potential infection and residence in non-human animal hosts and suggests the possibility that norovirus may be a zoonotic pathogen.     

Origin of the high-frequency resonances in 1H NMR spectra of muscle tissue: an in vitro slow magic-angle spinning study

High-resolution slow magic-angle spinning (150 Hz) 1H PASS NMR spectroscopy is performed on intact excised rat m. tibialis anterior. Untreated muscles and muscles in vitro incubated in Krebs-Ringers buffer based on deuterium oxide are investigated. In the high-frequency region of the 1H NMR spectra, resonances from H4 (approximately 7.1-7.2 ppm) and H2 (approximately 8.2-8.5 ppm) in histidine are observed. In addition, a resonance appears at 6.7 ppm for the untreated muscles. However, this resonance is absent in muscles following incubation in deuterium oxide. On the basis of its behavior in deuterium oxide combined with supplementary measurements for creatine solutions, the 6.7 ppm resonance is ascribed to the amino protons in creatine. Moreover, the present study demonstrates that the observation of the 6.7 ppm resonance depends on pH, which explains earlier reports stating its occasional appearance. Finally, measurements on solutions of ATP/AMP and histidine indicate that both ATP/AMP and histidine contribute to the resonances at approximately 8.2-8.5 ppm in the 1H NMR spectra of muscle tissue.     

Grain characteristics, chemical composition, and functional properties of rye (Secale cereale L.) as influenced by genotype and harvest year

Grain characteristic, chemical composition, and functional properties of rye were measured in 19 different cultivars grown in one location in up to 3 years. The cultivars included 8 adapted hybrids, 7 adapted population cultivars, and 4 nonadapted population cultivars. The results showed a significant influence of both harvest year and genotype on grain characteristics, chemical composition, and functional properties of the grain. Multivariate data analysis confirmed that the variations in the data were explained by yearly and genotype differences. Calculations of variance components showed that the variations in plant height, harvest yield, and protein content were mainly due to genotype differences and to a lesser extent to differences among harvest years. The kernel weight, hardness index, and content of dietary fiber components, however, were more strongly influenced by the harvest year than by the genotype. Differences in starch properties measured by falling number (FN), amylograph peak viscosity, and temperature at peak viscosity were more strongly influenced by harvest year. The water absorption was strongly influenced by genotype effects, compared to yearly differences. FN and amylograph peak temperature were positively correlated (r = 0.94). No correlation was found between the water absorption and the relative proportion of water-extractable arabinoxylan (AX) compared to the total AX content. However, the degree of ferulic acid cross-linking showed a negative correlation (r = -0.70) with the water absorption.     

Electrical stunning of farmed Atlantic cod Gadus morhua L.: a comparison of an industrial and experimental method

An industrial and experimental electrical method for stunning farmed Atlantic cod in air and seawater (SW), respectively, were compared. The impacts of sedation with AQUI‐S^? and exercise to exhaustion before electrical stunning were also assessed to monitor the possible depletion of rested muscle energy levels by electrical stunning. Stress (blood glucose, haematocrit, muscle pH, muscle excitability, high‐energy phosphates and rigor mortis) and flesh quality (fillet texture, colour, liquid leakage (LL), gaping, residual blood and K‐value) were assessed. For the industrial stunning method, an average of 41 V, 0.2 A dc was applied to individual cod for 18–27 s. For the SW method, a bipolar square wave current (170 Hz, 33% duty cycle) was applied for 5 s. After stunning, recovery was prevented by exsanguination in chilled SW. There were no differences (P>0.05) between the two stunning methods except for a higher ultimate fillet pH for cod stunned in air 8 days postmortem. Exercise before stunning depleted muscle energy levels at slaughter, increased LL and fillets had redder and darker flesh after storage on ice for 8 days. Electrical stunning (in air) of AQUI‐S^?‐treated fish partly depleted muscle energy levels (pH 7.3, ATP 18.7 μmol g^?1, PCr 70.1 μmol g^?1). However, flesh quality was not affected. Unless pre‐rigor filleting is the chosen processing strategy, electrical stunning of cod seems to be a promising stunning method.     

Regrowth and dry matter allocation in Quercus robur (L.) seedlings root pruned prior to transplanting

Two-year seedlings of Quercus robur (pedunculateoak) were root-pruned before transplanting in order toevaluate the importance of coarse versus fine roots onregrowth. Root systems were pruned by leaving c. 19,13 or 7 cm root from the root collar. Alternatively,coarse roots (>2 mm in diameter) were removed, leaving only the taproot and the fine roots (<2 mm)attached, or fine roots were removed from coarse rootsand taproot. Growth of shoots and roots after onegrowing season was compared to an unpruned controlunder standard nursery conditions. Seedlings rootpruned to 19, 13 or 7 cm were further tested undercompetition achieved by transplanting into a mixtureof clover and grass. Pruning of the root systemsignificantly reduced regrowth in terms of total plantDW in accordance with the severity of pruning, shootDW being more affected than root DW. Removal of coarseroots depressed final root DW whereas removal of fineroots reduced shoot DW and hence root:shoot ratioincreased. The study suggests that fine and coarseroots have different roles in root:shoot allocation.The competition test increased root:shoot ratioindicating that competition induced seedlings toallocate more of their resources into growth of theroot system.