Electrical stunning followed by decapitation or chilling of African catfish (Clarias gariepinus): assessment of behavioural and neural parameters and product quality   总被引：1，自引：0，他引：1  

Bert Lambooij  Karen Kloosterboer  Marien A Gerritzen  Geert André  Martine Veldman  & Hans Van De Vis 《Aquaculture Research》2006,37(1):61-70

The objective of this study was to assess neural and behavioural responses in farmed African catfish (Clarias gariepinus) upon electrical stunning in combination with decapitation or chilling. To assess the possibility of scaling up one or both experimental methods, two trials were performed in an experimental setting. The product quality of the collected samples was compared with the currently applied industrial method: live chilling. After electrical stunning in combination with decapitation, the fish showed spikes alternated with theta and delta waves on the EEG, followed by minimal brain activity after 20±10 s. The same traces on the EEGs were observed after electrical stunning in combination with chilling. Here, minimal brain activity occurred after 22±11 s. Within a confidence level of 95%, the percentage of African catfish that was effectively stunned after administration of an electrical current of 1.5 A dm⁻², 300 V (50 Hz a.c.), followed by decapitation or chilling was above 91%. The analysis yield and evolution of liquid loss showed significant (P<0.05) differences among the batches, which could be explained by the stunning method used. The course values of the pH in the different batches were significantly (P<0.05) dependent on the stunning method, sex and location (visceral or skin side). It is concluded that African catfish can be stunned effectively using electrical stunning in a water tank, followed by decapitation or chilling in ice. Dutch commercial processors prefer to combine electrical stunning with chilling in flake ice in a rotating tumbler, as the outer slime layer is then removed, which facilitates further processing.  相似文献   

A feasible method for humane slaughter of eel (Anguilla anguilla L.): electrical stunning in fresh water prior to gutting     

E Lambooij  J W van de Vis  H Kuhlmann  W Münkner  J Oehlenschläger  R J Kloosterboer  & C Pieterse 《Aquaculture Research》2002,33(9):643-652

It was observed that farmed eels could be rendered unconscious and insensible instantaneously by passing an electrical current through fresh water. The general epileptiform insult on the EEG was characterized by a tonic/clonic and an exhaustion phase. After stunning, the ECG (electro‐cardiogram) revealed fibrillation. The electrical stunning parameters were on average 194 ± 4 V and 0.636 ± 0.040 A/dm² for 1.6 ± 0.4 s. Within a confidence level of 95%%, taking into account the number of animals with a reliable EEG (n = 29), at least 93% of all eels are effectively stunned in fresh water by an average current of 0.636 ± 0.040 A/dm². The behaviour of groups of five eels, which were able to move freely in the water was observed before and after stunning with 50 V and 0.17 A/dm². After 3‐s stunning, two eels were turned upside down. They changed to a normal position after 10 and 13 s respectively. Subsequently, all eels were very active in swimming behaviour and stopped swimming after 75 s. When stunned for a longer duration, all eels were turned upside down and stopped breathing for a limited period of time. In the last experiment the eels were stunned in fresh water (500 μS) with a voltage of 200 V for approximately 1 s, which was followed by 50 V for 5 min. As soon as the stunning started the water was de‐oxygenated by flushing nitrogen to kill the eels by suffocation during the period of unconsciousness and insensitivity. The oxygen saturation decreased from 74 ± 10 to 23 ± 11% at 22 °C. After stunning no brain activity and no responses to pain stimuli were observed on the EEG. The heart rate increased (P < 0.05) after stunning, which was followed by a significant decrease. Only 1 out of 18 eels returned partially from upside down to a normal position 2 h after stunning; however, the eel did not respond to pain stimuli in behaviour. The developed stunning procedure can be recommended for humane slaughter of 50‐kg batches of eels.  相似文献   

In vitro antioxidant and ex vivo protective activities of green and roasted coffee     

Daglia M  Papetti A  Gregotti C  Bertè F  Gazzani G 《Journal of agricultural and food chemistry》2000,48(5):1449-1454

The antioxidant properties of green and roasted coffee, in relation to species (Coffea arabica and Coffea robusta) and degree of roasting (light, medium, dark), were investigated. These properties were evaluated by determining the reducing substances (RS) of coffee and its antioxidant activity (AA) in vitro (model system beta-carotene-linoleic acid) and ex vivo as protective activity (PA) against rat liver cell microsome lipid peroxidation measured as TBA-reacting substances. RS of C. robustasamples were found to be significantly higher when compared to those of C. arabica samples (p < 0.001). AA for green coffee samples were slightly higher than for the corresponding roasted samples while PA was significantly lower in green coffee compared to that of all roasted samples (p < 0.001). Extraction with three different organic solvents (ethyl acetate, ethyl ether, and dichloromethane) showed that the most protective compounds are extracted from acidified dark roasted coffee solutions with ethyl acetate. The analysis of acidic extract by gel filtration chromatography (GFC) gave five fractions. Higher molecular mass fractions were found to possess antioxidant activity while the lower molecular mass fractions showed protective activity. The small amounts of these acidic, low molecular mass protective fractions isolated indicate that they contain very strong protective agents.  相似文献   

Mutational analysis of the tyrosine phosphatome in colorectal cancers   总被引：1，自引：0，他引：1  

Wang Z  Shen D  Parsons DW  Bardelli A  Sager J  Szabo S  Ptak J  Silliman N  Peters BA  van der Heijden MS  Parmigiani G  Yan H  Wang TL  Riggins G  Powell SM  Willson JK  Markowitz S  Kinzler KW  Vogelstein B  Velculescu VE 《Science (New York, N.Y.)》2004,304(5674):1164-1166

Tyrosine phosphorylation, regulated by protein tyrosine phosphatases (PTPs) and kinases (PTKs), is important in signaling pathways underlying tumorigenesis. A mutational analysis of the tyrosine phosphatase gene superfamily in human cancers identified 83 somatic mutations in six PTPs (PTPRF, PTPRG, PTPRT, PTPN3, PTPN13, PTPN14), affecting 26% of colorectal cancers and a smaller fraction of lung, breast, and gastric cancers. Fifteen mutations were nonsense, frameshift, or splice-site alterations predicted to result in truncated proteins lacking phosphatase activity. Five missense mutations in the most commonly altered PTP (PTPRT) were biochemically examined and found to reduce phosphatase activity. Expression of wild-type but not a mutant PTPRT in human cancer cells inhibited cell growth. These observations suggest that the mutated tyrosine phosphatases are tumor suppressor genes, regulating cellular pathways that may be amenable to therapeutic intervention.  相似文献   

Crystal structure of the long-chain fatty acid transporter FadL     

van den Berg B  Black PN  Clemons WM  Rapoport TA 《Science (New York, N.Y.)》2004,304(5676):1506-1509

The mechanisms by which hydrophobic molecules, such as long-chain fatty acids, enter cells are poorly understood. In Gram-negative bacteria, the lipopolysaccharide layer in the outer membrane is an efficient barrier for fatty acids and aromatic hydrocarbons destined for biodegradation. We report crystal structures of the long-chain fatty acid transporter FadL from Escherichia coli at 2.6 and 2.8 angstrom resolution. FadL forms a 14-stranded beta barrel that is occluded by a central hatch domain. The structures suggest that hydrophobic compounds bind to multiple sites in FadL and use a transport mechanism that involves spontaneous conformational changes in the hatch.  相似文献   

CO2 elicits long-term decline in nitrogen fixation     

Hungate BA  Stiling PD  Dijkstra P  Johnson DW  Ketterer ME  Hymus GJ  Hinkle CR  Drake BG 《Science (New York, N.Y.)》2004,304(5675):1291

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Mutational analysis of the tyrosine kinome in colorectal cancers     

Bardelli A  Parsons DW  Silliman N  Ptak J  Szabo S  Saha S  Markowitz S  Willson JK  Parmigiani G  Kinzler KW  Vogelstein B  Velculescu VE 《Science (New York, N.Y.)》2003,300(5621):949

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Coordinate regulation of transcription and splicing by steroid receptor coregulators     

Auboeuf D  Hönig A  Berget SM  O'Malley BW 《Science (New York, N.Y.)》2002,298(5592):416-419

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Differences between tight and loose cultures: a 33-nation study     

Gelfand MJ  Raver JL  Nishii L  Leslie LM  Lun J  Lim BC  Duan L  Almaliach A  Ang S  Arnadottir J  Aycan Z  Boehnke K  Boski P  Cabecinhas R  Chan D  Chhokar J  D'Amato A  Ferrer M  Fischlmayr IC  Fischer R  Fülöp M  Georgas J  Kashima ES  Kashima Y  Kim K  Lempereur A  Marquez P  Othman R  Overlaet B  Panagiotopoulou P  Peltzer K  Perez-Florizno LR  Ponomarenko L  Realo A  Schei V  Schmitt M  Smith PB  Soomro N  Szabo E  Taveesin N  Toyama M  Van de Vliert E  Vohra N  Ward C  Yamaguchi S 《Science (New York, N.Y.)》2011,332(6033):1100-1104

With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.  相似文献   

Flow-microcalorimetry measurements of aerobic and anaerobic soil microbial activity     

Bert P. Albers  Friedrich Beese  Anton Hartmann 《Biology and Fertility of Soils》1995,19(2-3):203-208

Heat output can be used as an indicator of microbial activity and is usually measured in a microcalorimeter with closed ampoules. In long-term experiments particularly, interpretation of the data is hindered by the changing environment in the closed ampoules because of O₂ consumption and CO₂ enrichment. We used a combination of a flow-microcalorimeter and a gas chromatograph to measure the heat flux and CO₂ and N₂O production rates under controlled conditions. Simultaneous detection of the heat output and CO₂ emission allowed calculation of the calorimetric: CO₂ (Cal/CO₂) ratio. A mean ratio of-435 kJ mol^-1 CO₂ was detected in six different soils amended with glucose and incubated under aerobic conditions. This ratio indicated that CO₂ was the end-product of catabolism. In wet 10–12 mm soil aggregates of a gleyic vertisol amended with glucose, values of-285 kJ mol^-1 CO₂ under an aerobic and-141 kJ mol^-1 CO₂ under a N₂ atmosphere was determined. These findings indicated that fermentative metabolism occurred. The Cal/CO₂ ratio was not affected when enough NO _inf3 ^sup- was available and denitrification processes (N₂O production) were possible.  相似文献