Presence and dehydration of ikaite, calcium carbonate hexahydrate, in frozen shrimp shell.     

A Mikkelsen  A B Andersen  S B Engelsen  H C Hansen  O Larsen  L H Skibsted 《Journal of agricultural and food chemistry》1999,47(3):911-917

Ikaite, calcium carbonate hexahydrate, has by means of X-ray diffraction analyses of frozen samples been identified as the mineral component of the white spots formed in the shell of frozen shrimp during storage. When the shrimp thaw and the shell material is dried and kept at room temperature, ikaite rapidly transforms into a mixture of anhydrous calcium carbonate forms. X-ray diffraction analyses and Raman spectra of synthetic ikaite as well as the dehydration product confirm the assignments, and the rate constant for dehydration is approximately 7 x 10(-)(4) s(-)(1) at ambient temperature. Differential scanning calorimetry showed that dehydration of synthetic ikaite is an entropy-driven, athermal process and confirms that a single first-order reaction is rate-determining. Ikaite is found to be stable in aqueous solution at temperatures below 5 degrees C and in the shell of frozen shrimps but decomposes on thawing to form anhydrous calcium carbonates.  相似文献   

Efficient production of doubled haploid wheat plants by in vitro treatment of microspores with trifluralin or APM   总被引：4，自引：0，他引：4  

N. J. P. Hansen  S. B. Andersen 《Plant Breeding》1998,117(5):401-405

Isolated microspore cultures from two doubled haploid (DH) lines of wheat, Triticum aestivum L., were used to develop an in vitro chromosome-doubling protocol. During the initial 24 h or 48 h of culture the microspores were treated with either of the two antimicrotubule herbicides trifluralin or amiprophos-methyl (APM) in concentrations ranging from 0.1 μM to 10μM. Untreated control cultures yielded 209 embryos per 100000 microspores, which is the equivalent of one spike. Among the regenerated plantlets 67% were green, and 15% of the flowering plants were spontaneously chromosome doubled. Treatments with both the herbicides had a significant effect on chromosome doubling, measured as the percentage of fertile regenerants. With the best combination of treatment duration (48 h) and herbicide concentration (10/μM) the percentage of fertile plants among regenerants could be increased up to 74% with APM and up to 65% with trifluralin. The largest numbers of DH plants per spike could be obtained with herbicide concentrations at 1–3 μM. Treatments with either herbicide at these concentrations resulted in an estimated average between the two genotypes of 27 DH plants per 100 000 microspores. These results demonstrate the high potential of APM and trifluralin as chromosome-doubling agents in isolated microspore cultures. The in vitro treatment integrated into tissue culture procedures will constitute an efficient method for chromosome doubling in future wheat breeding  相似文献   

Origin of multiexponential T(2) relaxation in muscle myowater.   总被引：5，自引：0，他引：5  

H C Bertram  A H Karlsson  M Rasmussen  O D Pedersen  S D?nstrup  H J Andersen 《Journal of agricultural and food chemistry》2001,49(6):3092-3100

To obtain a further understanding of the nature of the multiexponential T(2) relaxation seen in muscle tissue water (myowater), relaxation measurements were carried out on whole, minced, and homogenized pork of three different qualities with regard to water-holding capacity (normal, red soft exudative, and dark firm dry). Whole, minced, and homogenized pork all resulted in multiexponential T(2) relaxation (three components) independently of the quality, even though microscopic studies on homogenized meat revealed considerable disruption of the macroscopic structure. This states that the relaxation behavior in meat cannot be explained by intra-/extracellular compartmentalization of the water as suggested in earlier studies. Subsequent studies of T(2) relaxation in either whole meat, where the structure integrity was changed by the introduction of dimethyl sulfoxide (membrane disruption) or urea (protein denaturation), or minced meat with added NaCl (inter-/intraprotein interactions) lead to the suggestion that in whole meat (i) the fastest relaxation component reflects water tightly associated with macromolecules, (ii) the intermediate relaxation component reflects water located within highly organized protein structures, for example, water in tertiary and/or quaternary protein structures and spatials with high myofibrillar protein densities including actin and myosin filament structures, and (iii) the slowest relaxation component reflects the extra-myofibrillar water containing the sarcoplasmatic protein fraction. Finally, relaxation patterns in heat-set gels of superprecipitated actomyosin and bovine serum albumin similar to that identified in whole meat support the proposed nature of T(2) relaxation in muscle myowater.  相似文献   

Analysis of metsulfuron-methyl in soil by liquid chromatography/tandem mass spectrometry. Application to a field dissipation study.     

R Bossi  P Seiden  S M Andersen  C S Jacobsen  J C Streibig 《Journal of agricultural and food chemistry》1999,47(10):4462-4468

An analytical method is described for the extraction of metsulfuron-methyl from soil at sub-parts per billion levels (LOQ = 0.2 microgram kg(-1)). The herbicide was quantitatively determined and identified by ESI LC/MS/MS. The method has been applied to a field dissipation study in which metsulfuron-methyl was applied to spring barley at three dosage rates: 4, 8, and 16 g of active ingredient ha(-)(1). The results of 2 years are presented. The dissipation rate of metsulfuron-methyl in topsoil was very rapid, with a calculated half-life of 6.5 days. Laboratory mineralization studies with native soils in contrast to autoclaved soils indicated that microbial degradation of (14)C-labeled metsulfuron-methyl and (14)C-labeled 2-amino-4-methoxy-6-methyl-1,3,5-triazine in soil microcosms is an important factor for the complete degradation of metsulfuron-methyl in the field. However, the mineralization rate of the sulfonamide was much higher.  相似文献   

Comparative effects of partial root-zone drying and deficit irrigation on nitrogen uptake in potatoes (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.)     

Huiqun Wang  Fulai Liu  Mathias N. Andersen  Christian R. Jensen 《Irrigation Science》2009,27(6):443-448

The effects of partial root-zone drying (PRD) as compared with deficit irrigation (DI) and full irrigation (FI) on nitrogen (N) uptake and partitioning in potato (Solanum tuberosum L.) were investigated. Potato plants were grown in split-root pots and were exposed to FI, PRD, and DI treatments at tuber bulking stage. Just before onset of the irrigation treatment, each plant received 0.6 g N (in the form of urea) with 5% of which was ¹⁵N-labeled. After 4 weeks of irrigation treatments (i.e., one drying/wetting cycles completed in the PRD treatment), the plants were harvested and plant dry mass and N content were determined. The results showed that although the plant dry mass was not affected by the irrigation treatments, due to a reduced water use by the plant, both the PRD and DI treatments significantly increased crop water use efficiency. Compared with the FI and DI plants, PRD plants had significantly higher N contents in the leaves, stems and tubers; whereas, the ¹⁵N content in the plant organs was similar for the FI, PRD, and DI plants. It is suggested that not the root N uptake efficiency but the soil N availability was enhanced by the PRD treatment.  相似文献   

Der Maiszünsler (Pyrausta nubilalis Hübn.) als Hopfenschädling     

Andersen  K. 《Journal of pest science》1943,19(7-9):49-56

Ohne Zusammenfassung Mit 4 Abbildungen  相似文献   

Exposure and effects assessments of Bt-maize on non-target organisms (gastropods, microarthropods, mycorrhizal fungi) in microcosms   总被引：2，自引：2，他引：2  

Annette de Vaufleury  Paulina E. Kramarz  Philippe Binet  Jrome Cortet  Sandra Caul  Mathias N. Andersen  Emmanuelle Plumey  Michael Coeurdassier  Paul H. Krogh 《Pedobiologia》2007,51(3):185-ECOGEN

Potential differences between Bt-maize (MEB307 expressing the insecticidal Cry1Ab protein) and a near-isogenic non-Bt variety (Monumental) in their influence on the garden snail (Helix aspersa), soil microarthropods (Collembola, Actinedida, Acaridida, Gamasida and Oribatida) and mycorrhizal fungi were studied. Growing snails were caged in microcosms allowing the development of Bt or non-Bt-maize (Zea mays L.) on a sandy loam soil. After 3 months exposure, survival and growth of snails were similar in both treatments. Cry1Ab protein was detected in the Bt-maize leaves (22–42.2 μg Bt protein g⁻¹ dry wt), in the snail tissues (0.04–0.11 μg Bt-protein g⁻¹ dry wt) and in their faeces (0.034–5 μg Bt-protein g⁻¹ dry wt). Total soil microarthropod abundance and diversity were similar between control (non-Bt-maize) and the genetically modified (GM) Bt-maize microcosms. The mycorrhizal colonization of roots did not differ between Bt and non-Bt-maize (frequency of mycorrhizal roots was 88.7% and 83.3% respectively). The mycorrhizal infectivity of soils, expressed as MI₅₀ (minimum soil dry weight required to colonize 50% of plants) was measured using red clover. MI₅₀ was similar for soils where Bt or non-Bt-maize was cultivated for 4 months. The detection of Cry1Ab protein in the viscera and faeces of H. aspersa exposed to Bt-maize indicates that snails contribute to the transfer of the Bt-protein from plant to soil or snail predators. This may constitute an alternative route of exposure for Bt-protein in soil, but this was without a negative influence on mycorrhizal fungi or microarthropods. Results showed that Bt-maize was not toxic for the selected non-target species exposed for 3 or 4 months. The microcosms and analyses used in this study represent new methods for assessing effects of chronic exposure to GM plants of several diverse, yet ecologically and temporally associated species. As the soil organisms we studied can also be used in standardized ecotoxicological tests (XP X31-205-2 for mycorrhizal fungi, ISO 11267 for Collembola and ISO 15952 for snails), microcosm exposures represent a way to link laboratory and field methods for the ecotoxicological evaluation of GM plants.  相似文献   

Aldehyde-induced xanthine oxidase activity in raw milk     

Steffensen CL  Andersen HJ  Nielsen JH 《Journal of agricultural and food chemistry》2002,50(25):7392-7395

In the present study, the aldehyde-induced pro-oxidative activity of xanthine oxidase was followed in an accelerated raw milk system using spin-trap electron spin resonance (ESR) spectroscopy. The aldehydes acetaldehyde, propanal, hexanal, trans-2-hexenal, trans-2-heptenal, trans-2-nonenal, and 3-methyl-2-butenal were all found to initiate radical reactions when added to milk. Formation of superoxide through aldehyde-induced xanthine oxidase activity is suggested as the initial reaction, as all tested aldehydes were shown to trigger superoxide formation in an ultrahigh temperature (UHT) milk model system with added xanthine oxidase. It was found that addition of aldehydes to milk initially increased the ascorbyl radical concentration with a subsequent decay due to ascorbate depletion, which renders the formation of superoxide in milk with added aldehyde. The present study shows for the first time potential acceleration of oxidative events in milk through aldehyde-induced xanthine oxidase activity.  相似文献   

Decentralised water and wastewater treatment technologies to produce functional water for irrigation   总被引：1，自引：0，他引：1  

Adriano Battilani  Michele Steiner  Soren Nohr Back  Avi Schweitzer  Anita Forslund  Wolfram Klopmann  Mathias N. Andersen 《Agricultural Water Management》2010,98(3):385-402

The EU project SAFIR aimed to help farmers solve problems related to the use of low quality water for irrigation in a context of increasing scarcity of conventional freshwater resources. New decentralised water treatment devices (prototypes) were developed to allow a safe direct or indirect reuse of wastewater produced by small communities/industries or the use of polluted surface water. Water treatment technologies were coupled with irrigation strategies and technologies to obtain a flexible, easy to use, integrated management of the system. The challenge is to apply new strategies and technologies which allow using the lowest irrigation water quality without harming food safety or yield and fruit or derivatives quality. This study presents the results of prototype testing of a small-scale compact pressurized membrane bioreactor and of a modular field treatment system including commercial gravel filters and heavy-metal specific adsorption materials. Decentralised compact pressurised membrane biobooster (MBR), was able to remove up to 99.99% of the inlet Escherichia coli and 98.52% of total coliforms. E. coli was completely removed from irrigation water in 53% of the samples by the last MBR prototype version. In 2008, 100% of samples fulfilled WHO standards (1989) and Global Gap requirement for faecal contamination. MBR removed from inlet flow in the average 82% of arsenic, 82% of cadmium, 97% of chromium, 93% of copper and 99% of lead. Boron and manganese were not removed from permeate. The field treatment system (FTS) proved to be effective against faecal contamination when applied with its complete set up including UV treatment. The sole gravel filter and heavy metal removal device (HMR) cannot provide sufficient and steadily treatment for microbial contamination. Nevertheless, gravel filter can remove up to 60% of E. coli but the removal process was not stable nor predictable. FTS removed 76% of arsenic, 80% of cadmium and copper, 88% of chromium and lead, and up to 97% of zinc. Like the MBR, boron and manganese were not removed from the irrigation water. Gravel filter directly fed with secondary treated wastewater was found able to remove 41% of arsenic, 36% of cadmium and lead, 48% of chromium and 46% of copper. The residual heavy metals concentration after the gravel filter was further reduced by the HMR: 35% for arsenic, 22% for cadmium, 25% for chromium, 33% for copper and 53% for lead.  相似文献   

Effects of the extreme drought in 2003 on soil respiration in a mixed forest   总被引：2，自引：0，他引：2  

Petia S. Nikolova  Stephan Raspe  Christian P. Andersen  Raphael Mainiero  Helmut Blaschke  Rainer Matyssek  Karl-Heinz Häberle 《European Journal of Forest Research》2009,128(2):87-98

We present a field study on the drought effects on total soil respiration (SR_t) and its components, i.e., “autotrophic” (SR_a: by roots/mycorrhizosphere) and “heterotrophic” respiration (SR_h: by microorganisms and soil fauna in bulk soil), in a mature European beech/Norway spruce forest. SR_a and SR_h were distinguished underneath groups of beech and spruce trees using the root exclusion method. Seasonal courses of SR_a and SR_h were studied from 2002 to 2004, with the summer of 2003 being extraordinarily warm and dry in Central Europe. We (1) analyzed the soil temperature (T _s) and moisture sensitivity of SR_a and SR_h underneath both tree species, and (2) examined whether drought caused differential decline of SR_a between spruce and beech. Throughout the study period, SR_a of beech accounted for 45–55% of SR_t, independent of the soil water regime; in contrast, SR_a was significantly reduced during drought in spruce, and amounted then to only 25% of SR_t. In parallel, fine-root production was decreased during 2003 by a factor of six in spruce (from 750 to 130 mg l⁻¹ a⁻¹), but remained at levels similar to those in 2002 in beech (about 470 mg l⁻¹ a⁻¹). This species-specific root response to drought was related to a stronger decline of SR_a in spruce (by about 70%) compared to beech (by about 50%). The sensitivity of SR_a and SR_h to changing T _s and available soil water was stronger in SR_a than SR_h in spruce, but not so in beech. It is concluded that SR_a determines the effect of prolonged drought on the C efflux from soil to a larger extent in spruce than beech, having potential implications for respective forest types. This article belongs to the special issue "Growth and defence of Norway spruce and European beech in pure and mixed stands."  相似文献