Proteome analysis of the sarcoplasmic fraction of pig semimembranosus muscle: implications on meat color development   总被引：2，自引：0，他引：2  

Sayd T  Morzel M  Chambon C  Franck M  Figwer P  Larzul C  Le Roy P  Monin G  Chérel P  Laville E 《Journal of agricultural and food chemistry》2006,54(7):2732-2737

Two-dimensional electrophoresis was used to investigate sarcoplasmic protein expression in pig Semimembranosus muscles sampled 20 min after slaughter. Two groups (light and dark) of 12 animals were selected from 1000 pigs, based on meat L values measured 36 h postmortem. Twenty-two proteins or fragments (p < 0.05) were differentially expressed. Muscles leading to darker meat had a more oxidative metabolism, indicated by more abundant mitochondrial enzymes of the respiratory chain, hemoglobin, and chaperone or regulator proteins (HSP27, alphaB-crystallin, and glucose-regulated protein 58 kDa). Conversely, enzymes of glycolysis were overexpressed in the lighter group. Such samples were also characterized by higher levels of glutathione S-transferase omega, which can activate the RyR calcium channels, and higher levels of cyclophilin D. This protein pattern is likely to have severe implications on postmortem metabolism, namely, acceleration of ATP depletion and pH fall and subsequent enhanced protein denaturation, well-known to induce discoloration.  相似文献   

Wheat-kernel-associated endoxylanases consist of a majority of microbial and a minority of wheat endogenous endoxylanases     

Dornez E  Joye IJ  Gebruers K  Delcour JA  Courtin CM 《Journal of agricultural and food chemistry》2006,54(11):4028-4034

The endoxylanases associated with wheat kernels consist of wheat endogenous endoxylanases on one hand and kernel-associated microbial endoxylanases on the other hand. Assessment of their presence, based on analysis of their enzymic activity, can be expected to be hampered by the presence in wheat of high levels of endogenous endoxylanase inhibitors, which are able to inhibit the wheat-kernel-associated microbial endoxylanases. On the basis of preliminary experiments aimed at clarifying the distribution of the wheat-associated endoxylanases, a method to estimate total endoxylanase activities in wheat kernels was developed. Extensive washing of wheat kernels with universal buffer of pH 8.0 provided near-quantitative separation of the microbial endoxylanases located on the surface of wheat kernels from the endogenous endoxylanases and endoxylanase inhibitors located in such kernels. The microbial or endogenous nature of the endoxylanases was confirmed by making use of the inhibition specificity of endoxylanase inhibitors. Determination of the endoxylanase activity in the washing liquid, corresponding to the microbial endoxylanase population, and the washed kernels, corresponding to the endogenous endoxylanase population, allowed estimation of the total endoxylanase activities associated with the wheat kernel. Results showed that microbial endoxylanases can account for over 90% of the total wheat-associated endoxylanase activity and that the latter can be at least 5 times higher than the apparent endoxylanase activity.  相似文献   

Insight into the distribution of arabinoxylans, endoxylanases, and endoxylanase inhibitors in industrial wheat roller mill streams     

Dornez E  Gebruers K  Wiame S  Delcour JA  Courtin CM 《Journal of agricultural and food chemistry》2006,54(22):8521-8529

To gain insight into the distribution of arabinoxylans (AX), endoxylanases, and endoxylanase inhibitors in industrial wheat roller milling, all streams, that is, 54 flour fractions, 4 bran fractions, and the germ, were analyzed for ash, starch, and protein contents, alpha-amylase activity levels, total (TOT-AX) and water-extractable arabinoxylan (WE-AX) contents, endoxylanase activity levels, and endoxylanase inhibitor (TAXI and XIP) contents. In general, bran fractions were significantly richer in TOT-AX and WE-AX contents, endoxylanase activity levels, and endoxylanase inhibitor contents than germ and, even more so, than flour fractions. In the 54 different flour fractions, minimal and maximal values for TOT-AX and WE-AX contents differed by ca. 2-fold, whereas they differed by ca. 15-fold for endoxylanase activity levels. The latter were positively correlated with ash and negatively correlated with starch content, suggesting that the endoxylanase activity in flour is strongly influenced by the level of bran contamination. TAXI contents in the flour fractions varied ca. 4-fold and were strongly correlated with bran-related parameters such as ash content and enzyme activity levels, whereas XIP contents varied ca. 3-fold and were not correlated with any of the parameters measured in this study. The results can be valuable in blending and optimizing wheat flour fractions to obtain flours with specific technological and nutritional benefits.  相似文献   

New strategies for the elimination of polio from India     

Grassly NC  Fraser C  Wenger J  Deshpande JM  Sutter RW  Heymann DL  Aylward RB 《Science (New York, N.Y.)》2006,314(5802):1150-1153

The feasibility of global polio eradication is being questioned as a result of continued transmission in a few localities that act as sources for outbreaks elsewhere. Perhaps the greatest challenge is in India, where transmission has persisted in Uttar Pradesh and Bihar despite high coverage with multiple doses of vaccine. We estimate key parameters governing the seasonal epidemics in these areas and show that high population density and poor sanitation cause persistence by not only facilitating transmission of poliovirus but also severely compromising the efficacy of the trivalent vaccine. We analyze strategies to counteract this and show that switching to monovalent vaccine may finally interrupt virus transmission.  相似文献   

Comparable efficacy of a topical 0.0584% hydrocortisone aceponate spray and oral ciclosporin in treating canine atopic dermatitis     

Nuttall TJ  McEwan NA  Bensignor E  Cornegliani L  Löwenstein C  Rème CA 《Veterinary dermatology》2012,23(1):4-10, e1-2

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Role of waterlogging-responsive genes in shaping interspecific differentiation between two sympatric oak species     

Le Provost G  Sulmon C  Frigerio JM  Bodénès C  Kremer A  Plomion C 《Tree physiology》2012,32(2):119-134

Pedunculate (Quercus robur L.) and sessile oak (Quercus petreae Matt. Liebl.) are closely related species with a widely sympatric distribution in Europe. These two oak species are also known to display different ecological features, particularly related to their adaptation to soil waterlogging. Pedunculate oak grows in humid areas and can withstand high moisture content of the soil, whereas sessile oak requires drier soil with better drainage. The main goal of this study was to explore the role of gene expression contributing to differences in terms of waterlogging tolerance between these two species. We implemented a series of experiments aimed at evaluating whether differentially expressed genes between species are associated with their ecological preferences and underlie adaptive genetic divergence. Rooted cuttings of both species were grown in hydroponic conditions and subjected to gradual root hypoxia. White roots were sampled after 6, 12, 24 and 48 h. Real-time polymerase chain reaction (qPCR) was first used to monitor the expression of 10 known waterlogging-responsive genes, to identify discriminating sampling time points along the kinetics of hypoxia. Secondly, four subtractive suppressive hybridization libraries (sessile vs. pedunculate, pedunculate vs. sessile for early and late responses) were generated to isolate differentially expressed genes between species. A total of 2160 high-quality expressed sequence tags were obtained and annotated, and a subset of 45 genes were selected for qPCR analysis in a second independent factorial experimental design applying two stress durations per two species. Significant differences of gene expression between pedunculate and sessile oaks were detected, suggesting species-specific molecular strategies to respond to hypoxia. This study revealed that the ability of pedunculate oak to maintain glycolysis and fermentation under hypoxic conditions may help explain its tolerance to waterlogging.  相似文献   

Defoliation by processionary moth significantly reduces tree growth: a quantitative review   总被引：1，自引：0，他引：1  

Jean-Sébastien Jacquet  Christophe Orazio  Hervé Jactel 《Annals of Forest Science》2012,69(8):857-866

? Context

Forests are important carbon sinks, but increasing temperatures may favour increases in insect populations, resulting in greater damage to trees. This, in turn, would lead to lower levels of carbon sequestration, intensifying global warming.

? Aim

It is therefore important to predict the impact of insect defoliation on tree growth accurately. The main insect defoliators of conifers in Southern Europe and North Africa are pine and cedar processionary moths (Lepidoptera, Thaumetopoeidae).

? Method

We conducted a meta-analysis based on 45 study cases, to estimate the effect of processionary moth defoliation on tree growth.

? Result

Overall, processionary moth defoliation had a significant impact on tree growth, regardless of the tree and moth species considered. Mean relative tree growth loss increased with the rate of defoliation levelling out at ca. 50?%; it was significantly larger for young than for old trees.

? Conclusion

These results suggest that estimates of processionary moth defoliation could easily be incorporated into tree growth models, to predict the effect of processionary moth outbreaks on carbon sequestration in Mediterranean forests.  相似文献   

Modeling of light transmission under heterogeneous forest canopy: an appraisal of the effect of the precision level of crown description     

David Da Silva  Philippe Balandier  Frédéric Boudon  André Marquier  Christophe Godin 《Annals of Forest Science》2012,69(2):181-193

• Context  

Light availability in forest understory is essential for many processes; it is, therefore, a valuable information regarding forest management. However, its estimation is often difficult and direct measurements are tedious. Models can be used to compute understory light, but they often require a lot of field data to accurately predict light distribution, particularly in the case of heterogeneous canopies.  相似文献   

Wheat Bran AX Properties and Choice of Xylanase Affect Enzymic Production of Wheat Bran‐Derived Arabinoxylan‐Oligosaccharides     

Valerie Van Craeyveld  Emmie Dornez  Ulla Holopainen  Emilia Selinheimo  Kaisa Poutanen  Jan A. Delcour  Christophe M. Courtin 《Cereal Chemistry》2010,87(4):283-291

Wheat bran‐derived arabinoxylan‐oligosaccharides (AXOS) recently have been shown to potentially exert prebiotic effects. In this study, 15 bran samples obtained by milling different wheat cultivars were treated with xylanases from Hypocrea jecorina (XHJ), Aspergillus aculeatus (XAA), and Pseudoalteromonas haloplanktis (XPH) to assess the effect of bran source and xylanase properties on the AXOS yield and structure. The total arabinoxylan (AX) extraction yield was higher with XHJ (8.2–10.7%) and XAA (8.2–10.8%) than with XPH (6.9–9.5%). Irrespective of the enzyme, a significant negative correlation was observed between extraction yield and arabinose to xylose (A/X) ratio of bran AX (r = –0.7), but not between yield and bran AX level. The A/X ratio of the extracted material was 0.27–0.34 for all bran samples and all enzymes, which combined with yield data and microscopic analysis, indicated primary hydrolysis of aleurone and nucellar epidermis AX. The average degree of polymerization (avDP) of the extracted AX was very low for all enzymes (2–3), owing to the release of high levels of monomeric arabinose and xylose. The release of these monosaccharides could be ascribed to 1) the activity of wheat bran‐associated enzymes (arabinofuranosidases and xylosidases); 2) the hydrolytic properties of the xylanases themselves; and 3) the presence of xylosidases as contaminations in enzyme preparation, in that order of importance. Heat treatment of bran before xylanase treatment significantly decreased the levels of monomeric arabinose and xylose in the extract, without affecting the extraction yield, resulting in a higher avDP of 3–7, thus yielding true AXOS. Overall, for AXOS production, wheat cultivars with a low bran A/X ratio of the AX are preferable as starting materials, and inactivation of bran‐associated enzymes before incubation is desirable. The XHJ xylanase was the best enzyme for wheat bran‐derived AXOS production.  相似文献   

Pharmacokinetic and pharmacodynamic modelling of intravenous,intramuscular and subcutaneous buprenorphine in conscious cats     

Paulo VM Steagall  Ludovic Pelligand  Tatiana Giordano  Christophe Auberger  John W Sear  Stelio PL Luna  Polly M Taylor 《Veterinary anaesthesia and analgesia》2013,40(1):83-95

ObjectiveTo describe simultaneous pharmacokinetics (PK) and thermal antinociception after intravenous (IV), intramuscular (IM) and subcutaneous (SC) buprenorphine in cats.Study designRandomized, prospective, blinded, three period crossover experiment.AnimalsSix healthy adult cats weighing 4.1 ± 0.5 kg.MethodsBuprenorphine (0.02 mg kg^?1) was administered IV, IM or SC. Thermal threshold (TT) testing and blood collection were conducted simultaneously at baseline and at predetermined time points up to 24 hours after administration. Buprenorphine plasma concentrations were determined by liquid chromatography tandem mass spectrometry. TT was analyzed using anova (p < 0.05). A pharmacokinetic-pharmacodynamic (PK-PD) model of the IV data was described using a model combining biophase equilibration and receptor association-dissociation kinetics.ResultsTT increased above baseline from 15 to 480 minutes and at 30 and 60 minutes after IV and IM administration, respectively (p < 0.05). Maximum increase in TT (mean ± SD) was 9.3 ± 4.9 °C at 60 minutes (IV), 4.6 ± 2.8 °C at 45 minutes (IM) and 1.9 ± 1.9 °C at 60 minutes (SC). TT was significantly higher at 15, 60, 120 and 180 minutes, and at 15, 30, 45, 60 and 120 minutes after IV administration compared to IM and SC, respectively. IV and IM buprenorphine concentration-time data decreased curvilinearly. SC PK could not be modeled due to erratic absorption and disposition. IV buprenorphine disposition was similar to published data. The PK-PD model showed an onset delay mainly attributable to slow biophase equilibration (t_1/2k_e0 = 47.4 minutes) and receptor binding (k_on = 0.011 mL ng^?1 minute^?1). Persistence of thermal antinociception was due to slow receptor dissociation (t_1/2k_off = 18.2 minutes).Conclusions and clinical relevanceIV and IM data followed classical disposition and elimination in most cats. Plasma concentrations after IV administration were associated with antinociceptive effect in a PK-PD model including negative hysteresis. At the doses administered, the IV route should be preferred over the IM and SC routes when buprenorphine is administered to cats.  相似文献