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31.
This study evaluated the effect of methionine supplementation, predation risk and their interaction on gut histology, whole-body cortisol levels, and intestinal gene expression in zebrafish. A total of 360 one-year-old animals were maintained under two environmental conditions and fed diets containing different methionine sources. Fish were fed either a control diet (CTL, without methionine supplementation), a diet supplemented with dl -methionine (DLM), or a diet supplemented with methionine dipeptide (MM) in the absence (AP) of a predator or in the presence of the predator (PP) for 48 h or 20 days. Predator-induced stress for 20 days resulted in lower body weight. Zebrafish fed methionine-supplemented diets had higher weight gain than control fish. We found no effect of predation stress or methionine supplementation on cortisol level. Predation risk and methionine supplementation showed no interaction effect on dipeptide transporter gene expression. After 48 h of predation pressure, zebrafish had higher mRNA expression of SOD2, CAT and GPX1 in the gut. After 20 days of exposure to the predator, zebrafish fed methionine-supplemented diets had lower expression of GPX1, SOD2 and CAT than those diet CTL. Methionine dipeptide and free methionine supplementation improved growth, intestinal health and survivability of zebrafish both conditions.  相似文献   
32.
Studies were made to determine the rate of decomposition of some 14C-labeled microbial polysaccharides, microbial cells, glucose, cellulose and wheat straw in soil, the distribution of the residual 14C in various humic fractions and the influence of the microbial products on the decomposition of plant residues in soil. During 16 weeks from 32 to 86 per cent of the C of added bacterial polysaccharides had evolved as 14CO2. Chromobacterium violaceum polysaccharide was most resistant and Leuconostoc dextranicus polysaccharide least resistant. In general the polysaccharides, microbial cells, and glucose exerted little effect on the decomposition of the plant products. Upon incubation the 14C-activity was quickly distributed in the humic. fulvic and extracted soil fractions. The pattern of distribution depended upon the amendment and the degree of decomposition. The distribution was most uniform in the highly decomposed amendments. After 16 weeks the bulk of the residual activity from Azotobacter indicus polysaccharide remained in the NaOH extracted soil. From C. violaceum polysaccharide both the extracted soil and the humic acid fraction contained high activity. About 50–80 per cent of the residual activity from the 14C-glucose, cellulose and wheat straw amended soils could be removed by hydrolysis with 6 n HCl. The greater part of this activity in the humic acid fraction was associated with the amino acids and that from the fulvic acids and residual soils after NaOH extraction with the carbohydrates. About 8 16 per cent of the activity of the humic acid fraction was present in substances (probably aromatic) extracted by ether after reductive or oxidative degradation.  相似文献   
33.
The effects of a white wine enriched with polyphenols (PEWW) from Chardonnay grapes and of a sparkling red wine (SRW) from Pinot Noir and Chardonnay grapes were studied for the first time on early atherosclerosis in hamsters. Animals were fed an atherogenic diet for 12 weeks. They received by force-feeding PEWW, SRW, ethanol 12% (ETH), or water as control (mimicking a moderate consumption of approximately 2 red wine glasses per meal for a 70 kg human). Plasma cholesterol concentrations were lower in groups that consumed PEWW and SRW accompanied by an increase in the ratio apo A-1/apo B. Liver-specific activities of superoxide dismutase and catalase were significantly increased by PEWW (38 and 16%, respectively) and by SRW (48 and 15%, respectively). PEWW and ETH significantly increased plasma antioxidant capacity and vitamin A concentrations. Aortic fatty streak area (AFSA) was significantly strongly reduced in the groups receiving PEWW (85%) and SRW (89%) in comparison with the control. AFSA was reduced by ethanol to a lesser extent (58%). These data suggest that tannins from the phenolics-enriched white wine induce a protective effect against early atherosclerosis comparable to that produced by sparkling red wine containing tanins and anthocyanins and dissociated from the antioxidant action of these compounds.  相似文献   
34.
Exposure to high levels of pollution is a persistent problem in large cities throughout the world. The ability to predict the occurrence of a high level of a pollutant allows environmental authorities to take preventive measures, such as controlling the emission of pollution. Communities and officials can also take actions to reduce the exposure of susceptible groups in the population. Therefore, being able to estimate the behavior of a given pollutant is of great importance. In this article we use a Markov chain model to study this behavior. In order to do so, we consider the sequence of the daily maximum measurements of a pollutant and let successive intervals containing them follow a Markov chain of order K>-0. The novelty here is that we allow K to be a random variable and estimate it and the corresponding transition probabilities using a maximum a posteriori method. The results are used to perform estimations about the behavior of ozone levels in Mexico City.  相似文献   
35.
The effects of the phenolic compounds catechin (Cat), quercetin (Qer), and resveratrol (Res) present in red wine on early atherosclerosis were studied in hamsters. Hamsters (n = 32) were divided into 4 groups of 8 and fed an atherogenic diet for 12 weeks. They received by force-feeding 7.14 mL/(kg of body wt.day) Cat, Qer, or Res in water [2.856 mg/(kg of body wt.day) for Cat and 0.1428 mg/(kg of body wt.dday) for Qer and Res], mimicking a moderate consumption of alcohol-free red wine (equivalent to that supplied by the consumption of about two glasses of red wine per meal for a 70 kg human), or water as control. Plasma cholesterol concentration was lower in groups that consumed phenolics than in controls. The increase in plasma apolipoprotein (Apo) A1 concentration was mainly due to Cat (26%) and Qer (22%) and to a lesser extent, but nonsignificantly, Res (19%). Apo-B was not affected. Plasma antioxidant capacity was not improved, and there was no sparing effect on plasma vitamins A and E. Plasma iron and copper concentrations were not modified nor were liver super oxide dismutase and catalase activities. A sparing effect of Qer on liver glutathione peroxidase activity appeared, whereas Cat and Res exhibited a smaller effect. Aortic fatty streak area was significantly reduced in the groups receiving Cat (84%) or Qer (80%) or Res (76%) in comparison with the controls. These findings demonstrate that catechin, quercetin, and resveratrol at nutritional doses prevent the development of atherosclerosis through several indirect mechanisms.  相似文献   
36.
Eutypine, 4-hydroxybenzaldehyde, and 3-phenyllactic acid are some of the phytotoxins produced by the pathogens causing Eutypa dieback and esca disease, two trunk diseases of grapevine (Vitis vinifera). Known biocontrol agents such as Fusarium lateritium and Trichoderma sp. were screened for their ability to consume these toxins. Transformation time courses were performed, and an high-performance liquid chromatography-based method was developed to analyze toxin metabolism and to identify and quantify the converted products. The results show that the aldehyde function of eutypine was reduced to eutypinol, as by V. vinifera cv. Merlot, the cultivar tolerant to Eutypa dieback. We revealed a supplementary detoxification pathway, not known in Merlot, where the aldehyde function was oxidized to eutypinic acid. Moreover, some strains tested could further metabolize the transformation products. Every strain tested could transform 4-hydroxybenzaldehyde to the corresponding alcohol and acid, and these intermediates disappeared totally at the end of the time courses. When biological assays on cells of V. vinifera cv. Chasselas were carried out, the transformation products exhibited a lower toxicity than the toxins. The possibility of selecting new biocontrol agents against trunk diseases of grapevine based on microbial detoxification is discussed.  相似文献   
37.
The aim of this study was to evaluate the antiatherosclerotic effect of commercially available phenolic-rich extracts from grape seeds (ExGrape seeds, EGS; grape seed extract, GSE) and marc (ExGrape total, EGT) in cholesterol-fed hamsters and to investigate possible operating mechanisms. These extracts fed at a moderate dose mimicking two glasses of red wine per meal reduced plasma cholesterol (-11% on average) but did not affect plasma antioxidant capacity of hamsters. The extracts prevented the development of aortic atherosclerosis by 68% (EGS), 63% (EGT), and 34% (GSE). Elsewhere, in an ex vivo experiment using rat aortic rings, EGS (7 microg/mL) induced 77% endothelium-dependent relaxation, whereas EGT and GSE (30 microg/mL) induced 84 and 72%, respectively. These results suggests that phenolic extracts from grape seeds and marc are beneficial in inhibiting atherosclerosis by indirect mechanism(s).  相似文献   
38.
The effect of daily contact of a grape seed extract (GSE) on Caco-2 cell proliferation and differentiation was investigated. GSE at 400 mg/L was added to Caco-2 cells for 2 h a day after successive incubation in saliva, gastric, and pancreatic media. When applied at the beginning of the cell culture, GSE triggered inhibition of cell growth associated with a possible cytotoxic reaction. On the other hand, when the treatment was applied to confluent cells, treated cells displayed a higher protein content than control cells and a more developed brush border, with taller and denser microvilli. These observations were accompanied by stimulation of alkaline phosphatase activity, especially at day 5 postconfluency, with a 2.2-fold increase in comparison with the control. On the other hand, aminopeptidase N activity was inhibited throughout the differentiation period in GSE-treated cells to reach 28.8% of control cell activity on day 30. GSE did not affect either sucrase-isomaltase activity or cytoplasmic lactate dehydrogenase (LDH) activity, which otherwise appeared to be a good cellular marker. GSE treatment of Caco-2 cells thus inhibited their proliferation from seeding onward and stimulated both proliferation and differentiation after confluency.  相似文献   
39.
Tropical Animal Health and Production - The aim of this study was to evaluate the impact of increased shadow supply in integrated crop-livestock-forest systems on in vitro embryonic development and...  相似文献   
40.
The use of a concentrate emulsion of Melia azedarach green fruits and a suspension of the fungus Beauveria bassiana was evaluated in the control of Rhipicephalus microplus on artificially infested cattle. The evaluation was conducted following the protocol established by the Brazilian Agriculture Ministry. Five groups of 4 or 5 animals were allocated to one of the following treatments: emulsion concentrate of M. azedarach at 0.25% (T AZED 0.25%), emulsion concentrate of M. azedarach at 0.5% (T AZED 0.5%), B. bassiana at 2.4 × 10(8) conidia (T BASS), association of the concentrate of M. azedarach at 0.25% with B. bassiana at 2.4 × 10(8) conidia (T AZED 0.25%+BASS), and control (untreated). The association of the two compounds provided better results than any one isolated treatment, indicating compatibility or perhaps a synergy between M. azedarach and B. bassiana. This treatment resulted in fewer engorged females (129 ± 70) than in the control group (233 ± 82), showing high performance against all developmental stages of the tick. Results revealed an apparent synergistic effect of M. azedarach and B. bassiana in the control of R. microplus that should be further investigated.  相似文献   
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