"Untypical aging off-flavor" in wine: synthesis of potential degradation compounds of indole-3-acetic acid and kynurenine and their evaluation as precursors of 2-aminoacetophenone     

Hoenicke K  Borchert O  Grüning K  Simat TJ 《Journal of agricultural and food chemistry》2002,50(15):4303-4309

Kynurenine (1) and indole-3-acetic acid (2) are considered as potential precursors of 2-aminoacetophenone (3), which is regarded to be the aroma impact compound causing an "untypical aging off-flavor" (UTA) in Vitis vinifera wines. The mechanism of the formation of 3 was studied using model fermentation and model sulfuration media spiked with 1 or 2 as potential precursors. Possible degradation products such as kynurenamine (4) and kynurenic acid (5), or skatole (6), 2-oxoskatole (7), 2-formamidoacetophenone (8), 2-oxindole-3-acetic acid (9), and 3-(2-formylaminophenyl)-3-oxopropionic acid (10) were evaluated by HPLC-UV of the fermentation and sulfuration media and comparison with synthesized 7, 8, 9, and 10. The synthesis of the possible precursor 4-(2-aminophenyl)-2,4-dioxobutanoic acid (11), a proposed metabolite of 1 failed because a spontaneous cyclization yields 5 and N-oxo-kynurenic acid (12), but not 11. It could be shown that the formation of 3 is triggered by an oxidative degradation of 2 after sulfuration with potassium bisulfite via the intermediates 10 and 8. However, no formation of 3 occurred during sulfuration of a model wine spiked with 1 or during fermentation of a model must spiked with 1 or 2.  相似文献   

Growth-related micromorphological characteristics of the porcine common carotid artery     

Andrea Nies  Lilly Proft  Marie E. Nehring  Christian Gruber  Henrieke Sievers  Hana Hünigen  Ole Gemeinhardt  Kenneth C. Richardson  Bernhard Hiebl 《Anatomia, histologia, embryologia》2020,49(5):620-626

The purpose of this study was to gain knowledge about the micromorphology of the porcine common carotid artery (CCA) during the period of growth over the bodyweight range of 10–40 kg. CCA samples from German landrace pigs (DL) aged either 2 or 3 months (DL-2 and DL-3) were compared with samples from Göttingen minipigs (GM) aged either 18 or 40 months (GM-18 and GM-40) using transmitted light (phase-contrast mode) and transmission electron microscopy. The GM-18, GM-40 and the DL-3 groups had typical muscular artery histological characteristics. Contrasting to this, the 2-month-old DL pigs had a transitional artery type being characterized by a significantly higher proportion of elastic fibres and a significantly lower number of smooth muscle cells than did the 1 month older DL-3. During the period of maturation, the tunica media of the CCA in GM animals thickened by 1.3× and in DL animals by 2.5× resulting in an overall increased vessel wall thickness. The cumulated thickness of the tunica interna (endothelium, stratum subendotheliale and internal elastic lamina) and the tunica media (including the external elastic lamina) of DL-3 and GM-40 pigs were similar to each other and comparable to that of humans. With an increasing vessel wall thickness, the luminal diameter decreased in GM by 19% and in DL by 11%. Additionally, in the older age groups, GM-40 and DL-3, the internal elastic lamina principally was continuous, but there were also interrupted large segments of elastic lamina separated by gaps. In addition, the principal internal elastic lamina was duplicated in several places.  相似文献   

Modelling the advection and diffusion of eggs and larvae of Greenland halibut (Reinhardtius hippoglossoides) in the north-east Arctic   总被引：1，自引：0，他引：1  

Bjørn Ådlandsvik  Agnes C. Gundersen  Kjell H. Nedreaas  Anne Stene  Ole T. Albert 《Fisheries Oceanography》2004,13(6):403-415

Since the late 1980s there has been considerable uncertainty in recruitment levels of the north‐east Arctic stock of Greenland halibut (Reinhardtius hippoglossoides). The abundance of several year classes, originally considered very low at 0–3 yr age, appeared higher than expected at the age of 6+. This may be due to poor targeting of recruitment surveys of the younger year classes. The present work considers the transport and dispersion of eggs and larvae of Greenland halibut by numerical modelling in order to predict the locations of the initial recruitment grounds. Current fields from a 3D baroclinic hydrodynamic model are fed into a Lagrangian particle‐tracking model developed for the Barents Sea area. The particles are released into the current at the spawning field along the shelf slope from Lofoten to Bear Island (69–75°N). Vertically, the particles can follow a predefined depth‐by‐age curve or be kept at a fixed depth. This model system is used for different years to examine changes in the drift pattern. The results indicate that spawning location, transport depth and inflowing activity to the Barents Sea are important factors influencing the distribution of juveniles.  相似文献   

Microstructure and texture of fresh and smoked Atlantic salmon, Salmo salar L., fillets from fish reared and slaughtered under different conditions     

Sjofn Sigurgisladottir  Margret S. Sigurdardottir  Helga Ingvarsdottir  Ole J. Torrissen  Hannes Hafsteinsson 《Aquaculture Research》2001,32(1):1-10

This study was carried out to examine differences in microstructure and texture of fresh and smoked farmed Atlantic salmon Salmo salar L. fillets with different biological characteristics. The left fillet was analysed fresh and compared with the salted and smoked right fillet from each individual fish. Light microscopy and image analysing techniques were used to study both transversal and longitudinal sections of the muscle. The fish muscle fibres shrank during the salting and smoking process, but sarcomere length did not change. After smoking, a considerable number of fat globules were dispersed among the muscle fibres. The biological characteristics studied were based upon diploid and triploid fish held in both sea cages and land‐based tanks. Different starvation times were used and one group was stressed during slaughter. The cross‐sectional area of muscle fibres from triploid fish was found to be larger than from diploid fish, both in fresh and smoked fillets.  相似文献   

Optical properties of the pineal window of Atlantic salmon (Salmo salar L.)     

Trond Nordtug  Ole Kristia Berg 《Fish physiology and biochemistry》1990,8(6):541-546

The spectral composition and intensity of light penetrating different parts of fresh preparations of the upper part of the skull of Atlantic salmon (Salmo salar) (fork length 25–30 cm) was investigated. All measurements were made in an aqueous medium, by moving the tip of an optical fibre in a three dimensional lattice below preparations that were illuminated by a parallel light source from above. The intensity of the transmitted light showed a well-defined maximum just below the pineal groove. Light that penetrated the skull from a source vertically above was refracted to produce a focusing point in the approximate position of the pineal body. Light projected from angles of 45° relative to the vertical position was only slightly (25%) attenuated, thus indicating a wide acceptance angle. There was an almost uniform transmission of light (of 3%) between 500 and 700 nm. The transmittance of UV light (350 nm) was about 10% of that of green light. These differences are small when compared with the intensity range reported for the pineal light receptors. The transmission properties are discussed in relation to the known diurnal changes in the spectral composition of natural light.  相似文献   

Restoration of a channelized reach of the River Gelså, Denmark: Effects on the macroinvertebrate community     

Nikolai Friberg  Brian Kronvang  Lars M. Svendsen  Hans Ole Hansen  Mogens B. Nielsen 《水产资源保护:海洋与淡水生态系统》1994,4(4):289-296

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Von Bandt's Fish Catching Methods of the World (Fourth Edition)     

Ole Arve Misund 《Fish and Fisheries》2007,8(2):162-163

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猪的最佳维生素营养   总被引：1，自引：0，他引：1  

卢建华  覃矜 《国外畜牧学(猪与禽)》2002,(1):22-24

猪的维生素需要量是动态的 ,是随猪种、营养状况、饲养管理方式等的不同而不同的 ,维生素需要量推荐值也因人们维生素功能的认识不断加深而有所不同。因此 ,需要不断地对维生素需要量推荐值进行更新  相似文献   

Noninvasive assessment of the facilitation of the nociceptive withdrawal reflex by repeated electrical stimulations in conscious dogs     

Bergadano A  Andersen OK  Arendt-Nielsen L  Spadavecchia C 《American journal of veterinary research》2007,68(8):899-907

OBJECTIVE: To investigate the facilitation of the nociceptive withdrawal reflex (NWR) by repeated electrical stimuli and the associated behavioral response scores in conscious, nonmedicated dogs as a measure of temporal summation and analyze the influence of stimulus intensity and frequency on temporal summation responses. ANIMALS: 8 adult Beagles. PROCEDURES: Surface electromyographic responses evoked by transcutaneous constant-current electrical stimulation of ulnaris and digital plantar nerves were recorded from the deltoideus, cleidobrachialis, biceps femoris, and cranial tibial muscles. A repeated stimulus was given at 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, and 1.1 x I(t) (the individual NWR threshold intensity) at 2, 5, and 20 Hz. Threshold intensity and relative amplitude and latency of the reflex were analyzed for each stimulus configuration. Behavioral reactions were subjectively scored. RESULTS: Repeated sub-I(t) stimuli summated and facilitated the NWR. To elicit temporal summation, significantly lower intensities were needed for the hind limb, compared with the forelimb. Stimulus frequency did not influence temporal summation, whereas increasing intensity resulted in significantly stronger electromyographic responses and nociception (determined via behavioral response scoring) among the dogs. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs, it is possible to elicit nociceptive temporal summation that correlates with behavioral reactions. These data suggest that this experimental technique can be used to evaluate nociceptive system excitability and efficacy of analgesics in canids.  相似文献   

Spatial variability of glyphosate mineralization and soil microbial characteristics in two Norwegian sandy loam soils as affected by surface topographical features     

Marianne Stenrød  Marie-Paule Charnay  Ole Martin Eklo 《Soil biology & biochemistry》2006,38(5):962-971

The aim of this study was to investigate the possible influence of surface topographical features on the spatial variability of glyphosate degradation and some microbial characteristics in sandy loam soil. Soil samples were taken from the ploughed layer across an agricultural field after seedbed preparation for grain (Grue site), and down to 1 m depth under a ridge tilled field (Målselv site), both sites having similar soil textural characteristics (sandy loam soil). Laboratory experiments were performed looking at glyphosate mineralization and soil microbial activity at the Grue site, as well as microbial biomass, activity and substrate utilization patterns at the Målselv site. Microbial biomass and activity decreased, and substrate utilization patterns changed with increasing soil depth, reflecting naturally occurring changes in quantity and quality of soil organic carbon. Further, our results show that considerable spatial heterogeneity in the degradation rate of glyphosate and general carbon utilization exists even across small areas within a single agricultural field. This horizontal variability was observed over several spatial scales, and could not be clearly explained. It evidently arose from differences in environmental factors affecting microbial activity and growth, and topographical features controlling redistribution of water and matter flow patterns were correlated to the investigated soil microbial variables.  相似文献