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排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
Contamination of food chain by Polychlorinated biphenyls through use of pesticides, electric and industrial waste poses human health risk. In previous studies, PCB species were stated as endocrine disrupting pollutants and showed toxic health effects like cancerous and noncancerous in animals. The aim of this study was to investigate the levels of PCBs and its toxicity equivalence in food item from plant source to evaluate the health risk in Khanewal and Multan, Pakistan. Samples were collected and processed for further analysis of PCB species through GC/MS after extraction and clean up. The mean concentrations of PCBs ranged as 2.71–151.67 ng/g in beans and grains and 2.30–97.00 ng/g dry weight in vegetables and were lower than 200–3000 ng/g PCBs recommended by FDA tolerance level for all foods. The mean concentrations of two NDL-PCB species detected in all vegetables, beans and grains except S.indicum and T.aestivum were lower than maximum allowable concentration of non-dioxin like PCBs i.e. 40ngg?1 reported by European Commission. Mean TEQ of sum of 14 PCB species ranged as 1.52–5.91 ng-WHO-TEQg?1 in vegetables and 1.46–10.04 ng-WHO-TEQg?1 in beans and grains. The present study concluded that the mean concentrations and mean TEQs of PCB species in most of the vegetables, beans and grains were found safe but due to higher consumption rate of some vegetables and grains, posed the moderate level of risk for human health. This study emphasizes on an implement of the strict rules regarding the use of restricted chemicals to diminish the effluence in food chains. Current research will be useful in up gradation of effective measures to reduce the poisonous contribution of PCB sources and the sustainability of terrestrial ecosystem in the country.  相似文献   
2.
酸性硫酸盐土水改旱后土壤化学性状的变异初报   总被引:2,自引:1,他引:1  
探讨了酸性硫酸盐水稻土改为旱作后土壤化学性状的变异以及比较不同利用方式之间的经济效益.结果表明,酸性硫酸盐水稻土改种甜玉米和蔬菜后,土壤化学性状发生显著变化.耕层土壤酸度、水溶性硫酸根含量、土壤活性铝和活性铁含量均显著降低.经济效益得到显著提高.建议对水改旱后的环境效应进行深入研究以及进行定位观测,以便合理利用这一特殊的土壤资源  相似文献   
3.
多功能营养型蔬菜无土栽培基质的特性研究   总被引:16,自引:1,他引:15  
采用多功能营养型无土栽培基质进行黄瓜、番茄和辣椒无土栽培研究,结果表明,多功能营养型无土栽培基质肥力较高,养分基本平衡,相关微生物(如氨化菌、硝化菌和纤维素分解菌等)数量多,脲酶、转化酶和蛋白酶等活性高,有利于基质有机成分的转化,黄瓜,番茄加辣椒的产量较土壤栽培分别提高23.83%、27.34%和32.98%,辣椒产值增加180.85%,纯收入提高109.69%,产品质量均达到“无公害”蔬菜标准。  相似文献   
4.
It is suggested that colorectal cancer might be prevented by changes in diet, and vegetable consumption has been demonstrated to have a protective effect. Until now, little is known about the effects of vegetable consumption at the proteome level. Therefore, the effect of increased vegetable intake on the protein expression in the colonic mucosa of healthy mice was studied. Aim was to identify the proteins that are differentially expressed by increased vegetable consumption and to discriminate their possible role in the protection against colorectal cancer. Mice were fed four different vegetable diets, which was followed by analysis of total cellular protein from colonic mucosal cells by a combination of 2-DE and MS. We found 30 proteins that were differentially expressed in one or more diets as compared to the control diet. Six could be identified by MALDI-TOF MS: myosin regulatory light chain 2, carbonic anhydrase I, high-mobility group protein 1, pancreatitis-associated protein 3, glyceraldehyde-3-phosphate dehydrogenase and ATP synthase oligomycin sensitivity conferral protein. Alterations in the levels of these proteins agree with a role in the protection against colon cancer. We conclude that these proteins are suitable markers for the health effect of food on cancer. The observed altered protein levels therefore provide support for the protective effects of vegetables against colorectal cancer.  相似文献   
5.
The identification of genes and understanding of genes'' expression and regulation in common bean (Phaseolus vulgaris L.) is necessary in order to strategize its improvement using genetic engineering techniques. Generation of expressed sequence tags (ESTs) is useful in rapid isolation, identification and characterization of the genes. To study the gene expression in P. vulgaris pods tissue, ESTs generation work was initiated. Early stage and late stage bean-pod-tissues cDNA libraries were constructed using CloneMiner cDNA library construction kit. In total, 5972 EST clones were isolated using random method of gene isolation. While processing ESTs, we found lycopene β-cyclase (PvLCY-β) and β-carotene hydroxylase (PvCHY-β) gene''s cDNA. In carotenoid biosynthesis pathway, PvLCY-β catalyzes the production of carotene; and PvCHY-β is known to function as a catalyst in the production of lutein and zeaxanthin. To understand more about PvLCY-β and PvCHY-β, both strands of both cDNA clones were sequenced using M13 forward and reverse primers. Nucleotide and deduced protein sequences were analyzed and annotated using online bioinformatics tools. Results showed that PvLCY-β and PvCHY-β cDNAs are 1639 and 1107 bp in length, respectively. Analysis results showed that PvLCY-β and PvCHY-β gene''s cDNA contains an open reading frame (ORF) that encodes for 502 and 305 amino acid residues, respectively. The deduced protein sequence analysis results also showed the presence of conserved domains needed for PvLCY-β and PvCHY-β functions. The phylogenetic analysis of both PvLCY-β and PvCHY-β proteins showed it''s closeness with the LCY-β and CHY-β proteins from Glycine max, respectively. The nucleotide sequence of PvLCY-β and PvCHY-β gene''s cDNA and it''s annotation is reported in this paper.  相似文献   
6.
This work describes classification, functions, location, inhibition, activation, and therapeutic applications of proteases from snake venoms and vegetables. Snake venoms and vegetables can present toxins that unchain necrosis or proteolysis due to the direct cytotoxic action of venom proteases. These proteases are potential tools in the development of drugs for the prevention and treatment of several illnesses. We report herein mainly fibrinogenolytic metallo proteases and serine proteases (“thrombin-like”). These enzymes are extensively used in the treatment and prevention of thrombotic disorders, since they serve as defibrinogenating agents. The therapeutic uses of fibrin(ogen)olytic metallo proteases hold promise for clinical application due to potential in reversing the effects of thrombosis; this has been shown to be an alternative approach to the prevention and treatment of cardiovascular disorders, which are among the most prominent causes of mortality around the world. Plant proteases can be utilized for many cellular and molecular activities, in antibacterial and anticancer therapies, and in the treatment of snakebites, inhibiting snake venom activities such as blood-clotting, defibrinogenation, and fibrin(ogen)olytic and hemorrhagic actions. These toxins also display potential for clinical use in the treatment of hemostatic disorders.  相似文献   
7.
Summary Quantitative relationships for growth rate and its dependence on plant nitrogen concentration are developed from the results of experiments on potatoes, cereals and vegetables. The relationships appear to be of general applicability and most coefficients in them are similar for widely different crops.It is argued that during the main growing period (May–August inclusive) in Western Europe growth of crop dry matter may be limited by self regulatory mechanisms within the plant and is little affected by variations in the aerial environment when there is ample water and nutrients. Under these conditions both growth rate and the critical % N in the dry matter (the minimum % N at which growth rate is maximum) are simple functions of plant dry weight.It is deduced that when account is taken of the effect of plant weight on % N in the dry matter, growth rate is, as a close approximation, linearly related to % N until this reaches the critical value and constant at higher values.A computer simulation model based on these relationships enabled estimates to be made of the influence of measured plant-N concentrations on the increase, throughout the season, in the dry weight of potatoes and cereals grown with different levels of N fertilizer. There was good agreement between the estimates made in this way and the results of numerous field experiments.  相似文献   
8.
We aimed to explore whether vegetable consumption according to guidelines has beneficial health effects determined with classical biomarkers and nutrigenomics technologies. Fifteen lean (age 36 ± 7 years; BMI 23.4 ± 1.7 kg m−2) and 17 obese (age 40 ± 6 years; BMI 30.3 ± 2.4 kg m−2) men consumed 50- or 200-g vegetables for 4 weeks in a randomized, crossover trial. Afterward, all subjects underwent 4 weeks of energy restriction (60 % of normal energy intake). Despite the limited weight loss of 1.7 ± 2.4 kg for the lean and 2.1 ± 1.9 kg for the obese due to energy restriction, beneficial health effects were found, including lower total cholesterol, LDL cholesterol and HbA1c concentrations. The high vegetable intake resulted in increased levels of plasma amino acid metabolites, decreased levels of 9-HODE and prostaglandin D3 and decreased levels of ASAT and ALP compared to low vegetable intake. Adipose tissue gene expression changes in response to vegetable intake were identified, and sets of selected genes were submitted to network analysis. The network of inflammation genes illustrated a central role for NFkB in (adipose tissue) modulation of inflammation by increased vegetable intake, in lean as well as obese subjects. In obese subjects, high vegetable intake also resulted in changes related to energy metabolism, adhesion and inflammation. By inclusion of sensitive omics technologies and comparing the changes induced by high vegetable intake with changes induced by energy restriction, it has been shown that part of vegetables’ health benefits are mediated by changes in energy metabolism, inflammatory processes and oxidative stress.

Electronic supplementary material

The online version of this article (doi:10.1007/s12263-013-0343-9) contains supplementary material, which is available to authorized users.  相似文献   
9.
Unused inorganic nitrogen (Ninorg) left in agricultural soils will typically leach to deeper soil layers. If it moves below the root zone it will be lost from the system, but the depth of the root zone depends on the crop species grown. In this experiment we studied the effect of 3-year crop sequences, with different combinations of deep-rooted and shallow-rooted crops, on soil Ninorg dynamics to 2.5 m soil depth and the possibility of crop utilization of N leached to deep soil layers. We grew ten different crop sequences for 3 years. The crops and catch crops grown were selected to allow different sequences of deep-rooted and shallow-rooted crops. Very different rooting depths were obtained, from only 0.5 m (leek), to ∼1.0 m (ryegrass and barley), 1.5 m (red beet), 2.0 m (fodder radish and white cabbage) and more than 2.5 m by the chicory catch crop. The results showed a significant retention of Ninorg within the 2.5 m soil profile from one year to the next, but the retained N had leached to deeper parts of the profile during the winter season. Only little Ninorg was retained over two winter seasons. The retention in the deeper soil layers allowed Ninorg to be taken up by succeeding deep-rooted main crops or catch crops. The effects of crop rooting depth on Ninorg in the subsoil layers from 1.0 to 2.5 m were striking. White cabbage reduced Ninorg below 1.0 m with up to 113 kg N ha-1 during its growth. Grown after catch crops, leek and red beet left on average 60 kg N ha−1 less below 1.0 m than leek and red beet grown without a preceding catch crop. We conclude that it is possible to design crop rotations with improved nitrogen use efficiency by using the differences in crop rooting patterns; deep-rooted crops or catch crops can be used to recover Ninorg leached after previous crops, and catch crops can be grown before shallow-rooted crops to lift the deep Ninorg up to layers where these crops have their roots.  相似文献   
10.
Chinese hamster lung fibroblasts, genetically engineered for the expression of rat cytochrome P450 dependent monooxygenase 1A2 and rat sulfotransferase 1C1 (V79-rCYP1A2-rSULT1C1 cells), were utilized to check for possible protective effects of beverages of plant origin, fruits, vegetables, and spices against genotoxicity induced by 2-acetylaminofluorene (AAF) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Antigenotoxic activities of juices from spinach and red beets against AAF could be monitored with similar effectivity by the HPRT-mutagenicity test (IC50=0.64%; 2.57%) and alkaline single cell gel electrophoresis (comet assay; IC50=0.12%; 0.89%) which detects DNA strand breaks and abasic sites. Applying the comet assay, genotoxicity of PhIP could, however, be demonstrated only in the presence of hydroxyurea and 1-[β- -arabinofuranosyl]cytosine, known inhibitors of DNA repair synthesis. As expected, AAF and PhIP were unable to induce any genotoxic effects in the parent V79 cells. Genotoxic activity of PhIP was strongly reduced in a dose-related manner by green tea and red wine, by blueberries, blackberries, red grapes, kiwi, watermelon, parsley, and spinach, while two brands of beer, coffee, black tea, rooibos tea, morellos, black-currants, plums, red beets, broccoli (raw and cooked), and chives were somewhat less active. One brand of beer was only moderately active while white wine, bananas, white grapes, and strawberries were inactive. Similarly, genotoxicity of AAF was strongly reduced by green, black, and rooibos tea, red wine, morellos, black-currants, kiwi, watermelon, and spinach while plums, red beets, and broccoli (raw) were less potent. Broccoli cooked exerted only moderate and white wine weak antigenotoxic activity. With respect to the possible mechanism(s) of inhibition of genotoxicity, benzo[a]pyrene-7,8-dihydrodiol (BaP-7,8-OH) and N-OH-PhIP were applied as substrates for the CYP1A family and for rSULT 1C1, respectively. Morellos, black-currants, and black tea strongly reduced the genotoxicity of BaP-7,8-OH, onions, rooibos tea, and red wine were less potent while red beets and spinach were inactive. On the other hand, red beets and spinach strongly inhibited the genotoxicity of N-OH-PhIP, rooibos tea was weakly active while all other items were inactive. These results are suggestive for enzyme inhibition as mechanism of protection by complex mixtures of plant origin. Taken together, our results demonstrate that protection by beverages, fruits, and vegetables against genotoxicity of heterocyclic aromatic amines may take place within metabolically competent mammalian cells as well as under the conditions of the Salmonella/reversion assay [Food Chem. Toxicol. 32 (1994) 443; Mutat. Res. 341 (1995) 303].  相似文献   
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