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41.
Consumption of fruits and vegetables, which are rich in polyphenols, has been associated with a reduced risk of chronic diseases such as cancer. Dietary polyphenols have antioxidant and antiproliferative properties that might explain their beneficial effect on cancer prevention. The aim of this study was to investigate the effects of different pure polyphenols [quercetin, chlorogenic acid, and (-)-epicatechin] and natural fruit extracts (strawberry and plum) on viability or apoptosis of human hepatoma HepG2 cells. The treatment of cells for 18 h with quercetin and fruit extracts reduced cell viability in a dose-dependent manner; however, chlorogenic acid and (-)-epicatechin had no prominent effects on the cell death rate. Similarly, quercetin and strawberry and plum extracts, rather than chlorogenic acid and (-)-epicatechin, induced apoptosis in HepG2 cells. Moreover, quercetin and fruit extracts arrested the G1 phase in the cell cycle progression prior to apoptosis. Quercetin and strawberry and plum extracts may induce apoptosis and contribute to a reduced cell viability in HepG2 cells. 相似文献
42.
Guedes AP Amorim LR Vicente AM Ramos G Fernandes-Ferreira M 《Journal of agricultural and food chemistry》2003,51(5):1399-1404
The essential oil yields obtained by hydrodistillation of the aerial parts of Hypericum androsaemum cultivated plants varied from 0.94 to 4.09 mg/g of biomass dry weight, depending of the harvest time. The respective analyses performed by gas chromatography and gas chromatography-mass spectrometry revealed more than 80 compounds, 72 of which were identified. Most of the compounds were sesquiterpene hydrocarbons, which, depending of the harvest time, corresponded to 43-78% of the total essential oil. The other compounds were distributed as monoterpene hydrocarbons, oxygen-containing sesquiterpenes, n-alkanes, 1-alkenes, and oxygen-containing monoterpenes, these being a minor group. In H. androsaemum in vitro shoots, sesquiterpene hydrocarbons represented >80% of the respective essential oil. Differences in the essential oil composition were found depending on the harvest time and origin, in vivo versus in vitro, of the plant material. The essential oil sampled in November was characterized by the highest levels of sesquiterpene hydrocarbons and a high number of n-alkanes and 1-alkenes, from C(18) to C(28), whereas that sampled in June of the following year showed the highest levels of n-nonane and 1-octene as well as monoterpene hydrocarbons, the second most representative group. 相似文献
43.
This paper analyses the differences in soil moisture, runoff and sediment concentration resulting from land levelling works carried out before new vineyard establishment in a reference wine region of NE Spain. In low disturbed soils, low differences in soil moisture were observed, while in high disturbed soils, soil moisture and water infiltration of the surface were always lower than in the low disturbed ones, while soil sealing was higher in high disturbed than in the low disturbed soils. Differences in runoff and sediment concentrations were also observed. The most disturbed plot showed a higher sediment concentration in runoff, which together with higher runoff volumes gave higher erosion rates and soil losses than the low disturbed one. The differences within the most disturbed soils were high after high intensity rainfall events, while no significant variations were observed in the least disturbed ones. 相似文献
44.
Pereira AS Norsell M Cardoso JN Aquino Neto FR Ramos MF 《Journal of agricultural and food chemistry》2000,48(11):5226-5230
Methanol extracts of propolis from six different places, five in Rio de Janeiro state and one in S?o Paulo state, both in the Southeast of Brazil, were investigated using high-temperature high-resolution gas chromatography (HT-HRGC) and HT-HRGC-mass spectometry. The main purpose of the study was to establish the applicability of HT-HRGC as an analytical method for systematic studies of polar propolis fractions. Several compounds, including carbohydrates, phenolic acid derivatives, and high molecular weight compounds (e.g., wax esters of long chain fatty alcohols) could be readily characterized in the crude extracts by HT-HRGC-MS. HT-HRGC and HT-HRGC-MS were shown to be quick and informative tools for rapid analysis of crude polar extracts without cleanup. 相似文献
45.
Redesigning metabolic routes: manipulation of TOL plasmid pathway for catabolism of alkylbenzoates 总被引:22,自引:0,他引:22
Increasing quantities of man-made organic chemicals are released each year into the biosphere. Some of these compounds are both toxic and relatively resistant to physical, chemical, or biological degradation, and they thus constitute an environmental burden of considerable magnitude. Genetic manipulation of microbial catabolic pathways offers a powerful means by which to accelerate evolution of biodegradative routes through which such compounds might be eliminated from the environment. In the experiments described here, a catabolic pathway for alkylbenzoates specified by the TOL plasmid of Pseudomonas was restructured to produce a pathway capable of processing a new substrate, 4-ethylbenzoate. Analysis of critical steps in the TOL pathway that prevent metabolism of 4-ethylbenzoate revealed that this compound fails to induce synthesis of the catabolic enzymes and that one of its metabolic intermediates inactivates catechol 2,3-dioxygenase (C23O), the enzyme that cleaves the aromatic ring. Consequently, the pathway was sequentially modified by recruitment of genes from mutant bacteria selected for their production of either an altered pathway operon regulator that is activated by 4-ethylbenzoate or an altered C23O that is less sensitive to metabolite inactivation. The redesigned pathway was stably expressed and enabled host bacteria to degrade 4-ethylbenzoate in addition to the normal substrates of the TOL pathway. 相似文献
46.
Barbosa J Freitas A Moura S Mourão JL Noronha da Silveira MI Ramos F 《Journal of agricultural and food chemistry》2011,59(22):11927-11934
Nitrofurans were broadly used as an extremely effective veterinary antibiotic especially in pig and poultry production farms. Because of fears of the carcinogenic effects on humans, the nitrofurans were banned from use in livestock production in many countries, including the European Union. The present study examines the accumulation, distribution, and depletion of furaltadone and nifursol and of their tissue-bound metabolites [3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ) and 3,5-dinitro-salicylic acid hydrazine (DNSAH), respectively, in poultry edible tissues (muscle, liver, and gizzards) following administration to chickens of therapeutic and subtherapeutic concentrations of both compounds. Nitrofurans determination was performed by high-performance liquid chromatography-diode array detection and liquid chromatography-tandem mass spectrometry, respectively, for feeds and for poultry tissues. Furaltadone and nifursol, in very low concentrations, were found in samples of muscle, liver, and chicken's gizzard collected from slaughtered animals after 5 weeks of treatment and no withdrawal time period. When a withdrawal time period of 3 weeks was respected, no detectable nitrofuran parent compounds was observed in all of the studied matrices. For AMOZ, concentrations of 270 μg/kg in meat, 80 μg/kg in liver, and 331 μg/kg in gizzard were determined after administration of a medicated feed with furaltadone (132 mg/kg), 3 weeks after withdrawal of treatment. For DNSAH, the concentration values obtained are much lower than those observed for AMOZ. For meat, liver, and gizzard, DNSAH concentrations of 2.5, 6.4, and 10.3 μg/kg, respectively, were determined, after administration of a medicated feed with nifursol (98 mg/kg), 3 weeks after withdrawal of treatment. The gizzard could be considered a selected matrix for nitrofuran residues evaluation in poultry, due to its capacity of retaining either nitrofuran parent compounds or metabolites in higher concentrations, regardless of the administered dose or of the respected withdrawal time period. 相似文献
47.
Humberto J.O. Ramos 《Soil biology & biochemistry》2006,38(8):2481-2486
To achieve stable expression of the heterologous and reporter genes in the Bradyrhizobium genome, we constructed suicide plasmids capable of site-directed genomic integration of the gusA, gfp and nifA genes by homologous recombination into non-essential repeated sequences (RS-α), isolated from B. japonicum strain CPAC7 (SEMIA5080). In this report, we describe the strategies to construct the vectors and their use to obtain mutants with site-specific insertions. 相似文献
48.
Siani AC Tappin MR Ramos MF Mazzei JL Ramos MC De Aquino Neto FR Frighetto N 《Journal of agricultural and food chemistry》2002,50(12):3518-3521
A new chemotype of the aromatic Verbenaceae species Lippia alba Mill. N. E. Br. from southeastern Brazil has recently been shown to have a high content of linalool in the leaf essential oil. Vegetative propagation of this chemotype was conducted at six different locations in Brazil, and the variation of the content and the optical purity of linalool in the oils were verified. Yields (0.6-0.9%, hydrodistillation), chemical composition, linalool content, and optical purity of the oils from all the plants were compared, using GC-FID, GC-MS, chiral chromatography, and retention index calculation. No plant exceeded the matrix in linalool content (46.5 to 90.7%), and the chemical profile of the oils was the same for all the samples. Purification of linalool to a content close to 100% was effected by vacuum distillation of the crude oil. Chiral analysis showed exclusively the presence of S-linalool in all the crude oils and in the distilled samples. 相似文献
49.
L Ferrer R M Rabanal M Domingo J A Ramos D Fondevila 《Research in veterinary science》1988,44(2):194-196
This paper describes the demonstration of Leishmania donovani amastigotes in canine tissues by immunoperoxidase staining. An indirect immunoperoxidase method was applied to the organs of 20 dogs in which leishmaniasis was previously diagnosed. Haemosiderin pigment was eliminated with 5 per cent oxalic acid. Amastigotes of L donovani appeared as dark brown stained bodies which contrasted with haematoxylin stained host cells. No positively stained amastigotes could be seen in any of the sections incubated with control serum. The organs which more frequently showed leishmanids were: skin (macrophages and fibroblasts), liver, spleen, lymph nodes and bone marrow. In a few cases amastigotes were seen in kidneys, gut, adrenal glands, eyes and testicles. This technique is simple to perform, gives consistent results and allows unequivocal histopathological diagnosis of canine leishmaniasis. 相似文献
50.
J. M. Ramos J. Marinetto M. B. Garcia Del Moral L. F. Garcia Del Moral 《Journal of Agronomy and Crop Science》1994,173(2):106-112
In six field experiments conducted over 2 years, the effect of one or two cuttings on grain yield of triticale (× Triticosecale Wittmack) were investigated. In addition, the relationships between triticale grain yield its components were analysed.
Grain yield of the uncut plots invariably exceeded the plots with one or two cuttings, regardless of the environment or year. The reductions in grain yield caused by one cutting ranged from 27 % to 60 % under rainfed conditions and 18 % to 20 % under irrigation. With two cuttings the reduction was 45 % to 70 % for rainfed, and 35 % to 48 % for irrigated conditions.
The yield components which most influenced grain yield of triticale under cutting treatment were the number of ears m−2 in all six experiments and the number of grains per ear under rainfed conditions. At the rainfed sites in 1989 cuttings diminished the number of ears m−2 mainly by increasing plant mortality. Nevertheless, at the rainfed sites of 1990 and at the irrigated site of both years, the reduction in the number of ears m−2 with cuttings was due principally to a lower survival of tillers per plant. 相似文献
Grain yield of the uncut plots invariably exceeded the plots with one or two cuttings, regardless of the environment or year. The reductions in grain yield caused by one cutting ranged from 27 % to 60 % under rainfed conditions and 18 % to 20 % under irrigation. With two cuttings the reduction was 45 % to 70 % for rainfed, and 35 % to 48 % for irrigated conditions.
The yield components which most influenced grain yield of triticale under cutting treatment were the number of ears m