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31.
Gargouri B Nasr R ben Mansour R Lassoued S Mseddi M Attia H El Feki Ael F Van Pelt J 《Biological trace element research》2011,144(1-3):1449-1457
In a previous study, we have described oxidative stress during Epstein-Barr virus lytic cycle induction. Oxidative stress was evidenced by the observed high MDA levels and the decreased activities of antioxidant enzymes. We hypothesised that the lower activities of the antioxidant enzymes decrease were the result of either the excessive production of reactive oxygen radical species (ROS) or a negative regulation of the antioxidant enzyme gene expressions. In an attempt to clarify this situation, EBV lytic cycle was induced in Raji cell line by a non-stressing dose of 12-0-tetradecanoylphorbol-13-acetate. BZLF-1, superoxide dismutase, and catalase gene expressions were then analysed using semi-quantitative RT-PCR, simultaneously at a kinetic of 6, 12, 24, 36, and 48?h. ROS production was evaluated by chemiluminescence. A study was conducted to establish whether ROS production, BZLF-1, and the expression of antioxidant genes were inter-correlated. Induction of the lytic cycle resulted in increased expressions of the genes of superoxide dismutase and catalase, which began at 24?h (p?0.05) and reached a peak at 48?h (p?0.05). Significant increases of the ROS levels were observed in TPA-treated Raji cell line at 12?h, as compared with untreated cells, reaching a peak at 48?h after EBV lytic cycle induction. ROS production correlates positively with BZLF-1, SOD, and CAT gene expressions (p?0.05; r?=?0.913, r?=?0.978, and r?=?0.955, respectively). A positive correlation was also observed between BZLF-1 and antioxidant gene expressions (p?0.05; r?=?0.961 and r?=?0.987, respectively). In conclusion, the observed increases of the SOD and CAT gene expressions eliminate the hypothesis of a repression of the respective genes during the induction of the lytic cycle. On the other hand, the observed direct correlation between the BZLF-1 gene expression and the ROS production is indicative of a role of this gene in oxidative stress. 相似文献
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33.
This article proposes a reformulation of the social brain theory of schizophrenia. Contrary to those who consider schizophrenia to be an inherently human condition, we suggest that it is a relatively recent phenomenon, and that the vulnerability to it remained hidden among our hunter-gatherer ancestors. Hence, we contend that schizophrenia is the result of a mismatch between the post-Neolithic human social environment and the design of the social brain. We review the evidence from human evolutionary history of the importance of the distinction between ingroup and out-group membership that lies at the heart of intergroup conflict, violence, and xenophobia. We then review the evidence for the disparities in schizophrenia incidence around the world and for the higher risk of this condition among immigrants and city dwellers. Our hypothesis explains a range of epidemiological findings on schizophrenia related to the risk of migration and urbanization, the improved prognosis in underdeveloped countries, and variations in the prevalence of the disorder. However, although this hypothesis may identify the ultimate causation of schizophrenia, it does not specify the proximate mechanisms that lead to it. We conclude with a number of testable and refutable predictions for future research. 相似文献
34.
This study showed from the analysis of 180 droppings of the Grey Wagtail Motacilla cinerea harvested during a period of one year from the Babors Mountains (Bejaia, Algeria) that insects formed the main part of the diet (85.9% of identified items). The other food categories included arachnids, crustaceans and gastropods. Among the insects, Coleoptera (beetles) was the main order consisting of 37.4% of identified items. The most frequently recorded family was Baetidae (Ephemeroptera; 9.8%). At the prey-taxa level, an unidentified Baetidae was the most frequently encountered and represented 9.7% of the diet. This species was present in the diet throughout the year. Prey taxa classified as aquatic were more frequently encountered (54.2%) compared with those considered terrestrial. This study showed that seasonal fluctuations in the diet of Grey Wagtail were very weak. Prey size ranged from 0.2 to 30.5 mm, with an average of 8.9 mm. Overall, this study showed that Grey wagtail fed on species of a wide variety of taxa, with little variation across the year. 相似文献
35.
Najla Trabelsi Hanen Falleh Ines Jallali Alia Ben Daly Hafedh Hajlaoui Abderrazek Smaoui Chedly Abdelly Riadh Ksouri 《Acta Physiologiae Plantarum》2012,34(1):87-96
Changes in phenolic composition and biological activities were investigated in different Limoniastrum monopetalum L. organs. For that, 80% aqueous acetone extracts were used to estimate total phenolic contents and their antioxidant activities
were evaluated using DPPH· and O2·− radical scavenging activities and reducing power. The efficiency of organ extracts was tested against human pathogen strains.
Ultimately, acid hydrolysis of all organs was subjected to RP-HPLC for phenolic identification. Results showed that flower
extracts exhibited the highest polyphenol (65.42 GAE/g DW) and flavonoid (35.36 CE/g DW) contents. Stems were enriched in
condensed tannin content (21.4 mg CE/g DW) and displayed the best antiradical activities and the highest reducing power. Besides,
stem and gall extracts showed the highest efficiency against pathogenic bacteria as compared with those of flower. Concerning
the antifungal test, a slight activity was found in gall extracts. The RP-HPLC showed a difference in phenolic compounds that
varied as function of organ. In fact, the major phenolic compound varied as function of organ. Results suggest that L. monopetalum could be a promising source of biomolecules for therapeutic and nutraceutical industries and the difference between organs
may be related to their physiological role. 相似文献
36.
Gwena?lle Le Blay Riadh Hammami Christophe Lacroix Isma?l Fliss 《Probiotics and antimicrobial proteins》2012,4(4):250-258
Listeria monocytogenes is responsible for severe foodborne infections, which can be life-threatening especially for infants and elderly populations. The emergence of antibiotic-resistant pathogens has stimulated the search for new strategies, such as the use of bacteriocins, to prevent or cure foodborne infectious diseases in the intestine. In this study, we evaluated the efficacy of the bacteriocin pediocin PA-1 from Pediococcus acidilactici UL5 to inhibit Listeria ivanovii, used as a surrogate for L. monocytogenes, under physiological conditions of the terminal ileum, simulated in a continuous in vitro fermentation model. A fecal sample from a healthy adult was immobilized and propagated for 30?days in a continuous stirred tank reactor, fed with a nutritive medium simulating the ileal chime (pH 7.5). After reaching a pseudo-steady state, the reactor was inoculated five times with L. ivanovii to reach a final concentration of 107 CFU/ml within the reactor. Two spikes of L. ivanovii without adjunction of pediocin PA-1 served as control assays, and three other spikes were done to test the effects of three concentrations of pediocin PA-1 corresponding to 2, 3, and 5× the minimum inhibitory concentration (MIC) active against L. ivanovii. The concentration of L. ivanovii in the reactor was followed for 8?h using the PALCAM selective medium. The different groups of commensal bacteria were enumerated on selective medium or using fluorescence in situ hybridization. Our data showed that pediocin PA-1 is stable in the ileum conditions and that it is able to exert its inhibition activity against L. ivanovii in a dose-dependent manner. The addition of pediocin PA-1 at 5?×?MIC induced a complete disappearance of L. ivanovii (5 log reduction) within 5?h, compared to a reduction of 2 logs, corresponding to the washout phenomenon, when no pediocin PA-1 was added. Reduction of 0.8 and 1.3 logs within 8?h was also obtained with the addition of 2 and 3?×?MIC, respectively. The same experiment has shown that addition of pediocin-PA1 in the reactor had a negligible effect on the balance of commensal bacteria. 相似文献
37.
M. S. Azaza F. Mensi J. Ksouri M. N. Dhraief B. Brini A. Abdelmouleh M. M. Kraïem 《Zeitschrift fur angewandte Ichthyologie》2008,24(2):202-207
The use of green algae ulva meal (UM) (Ulva rigida) was evaluated as a replacement for soybean meal in a practical diet formulated to contain 28% crude protein, 7.50% lipid and 15 kJ gross energy g?1. Soybean meal was replaced by 0%, 10%, 20% and 30% of UM (diets U0, U1, U2 and U3, respectively). The feeding experiment was carried out in an open circulation system. Each diet treatment was applied to triplicate groups of 30 fish (21.37 ± 0.193 g average wet weight) per tank (400 L) arranged in a completely randomized design. The fish were hand fed to satiation four times daily between 07.00 and 18.00 hours for 75 days. There were no significant differences (P > 0.05) in growth performance among fish fed with diets U0, U1 and U2. However, fish fed diet U3 had significantly lower growth (P < 0.05) than those fed diets U0, U1 and U2. Fish fed the control diet (U0) and diets including 10% and 20% UM had significantly (P < 0.05) better daily weight gain, relative growth weight, specific growth weight and protein efficiencies ratio than those fed with diet U3. Feed conversion ratio increased with increasing UM content, but only the value found in fish fed with diet U3 differed significantly (P < 0.05) from all other treatments. Survival rates ranged between 91.11% and 93.33%. No feed‐related mortality was observed during the entire experimental period. Apparent protein digestibility (APD) of diets ranged from 87.06 to 69.91% and was lowest for fish fed with diet U3. In general, APD values decreased with increasing inclusion levels of UM, explained by the increase of anti‐nutritional factors and high non‐digestible fibre content. Compared to the control diet (U0), fish fed diets containing high levels of UM had lower levels of carcass lipid and higher levels of carcass moisture. Results show that this product can be included by up to 20% in practical male Nile tilapia diets with no detrimental effects. 相似文献
38.
The aim of this work was to study the effect of antimicrobial peptides: divergicin M35 and nisin A on Listeria monocytogenes LSD 530 potassium (K+) channels: ATP-sensitive (KATP), calcium-activated (BKCa), and depolarization-activated (Kv) types. Increase on K+ efflux and inhibition of cellular growth were observed after adding K+ channel activators pinacidil, NS1619, and cromakalim to divergicin M35. Increase in K+ efflux from log-phase cells was about 18 ± 1.1, 11 ± 0.63, and nmol mg−1 of cell dry weight (CDW) for pinacidil and NS1619, respectively, over the efflux obtained with divergicin M35 alone. Increases
in K+ efflux obtained by adding the same K+ channel activators to nisin A fit a completely different profile. Divergicin M35 activates K+ channels, particularly of the Kv and BKCa types and to a lesser extent the KATP type, causing K+ efflux and consequently cell death. 相似文献
39.
Effects of low doses of Li carbonate injected into mice. Functional changes in kidney seem to be related to the oxidative status 总被引:1,自引:0,他引:1
Effects of daily injections of lithium carbonate (20, 40 or 80 mg/kg body weight) during 14 and 28 days were investigated in Wistar mice. Attention was paid (1) to changes in concentrations of lithium, creatinine and urea in serum, (2) to level of oxidative stress by measuring lipids peroxidation level and catalase, superoxide-dismutase and glutathione-peroxidase activities, and (3) to changes in the histological structure of brain. The first intraperitoneal injection was followed by a transitory peak of lithium in the blood, reaching 0.25 mM and 1.1 mM and disappearing 6 and 12 h later for the 20 and 80 mg/kg doses, respectively. From the first to the last day of treatment, lithium concentrations in the blood, measured 12 h after the injections, increased from 0 to 0.11 mM (20 mg/kg dose) or 0.25 mM (80 mg/kg dose). The 80 mg/kg treatment induced a renal insufficiency evidenced by an increase of blood creatinine and urea levels. Lithium treatment was found to trigger an oxidative stress in kidney, but not in brain. In kidney, the lipid peroxidation level (TBARS) and the superoxide dismutase and catalase activities were increased. No change in glutathione peroxidase activity was detected. Histology of the brain cortex revealed interesting modifications: thicker neuronal cells and a denser network of dendrites, as compared to controls. 相似文献
40.
Falleh H Ksouri R Chaieb K Karray-Bouraoui N Trabelsi N Boulaaba M Abdelly C 《Comptes rendus biologies》2008,331(5):372-379
Polyphenols are bioactive molecules exhibiting a lot of scientific attention due to their multiple biological activities. This study compared phenolic contents and antioxidant activity in Cynara cardunculus L. organs and focus on leaf phenolic compounds identification by RP-HPLC and their antibacterial activity. The analyzed organs exhibited different total polyphenol contents (7-14.8 mg GAE g(-1) DW). Leaf and seed phenolic contents were similar and two times higher than those in flowers. The same tendency was observed for the amount of flavonoids and tannins. However, seed extracts displayed the highest DPPH. scavenging ability with the lowest IC50 value (23 microg ml(-1)), followed by leaves and flowers (over 50 microg ml(-1)). In contrast, leaves showed the highest capacity to quench superoxide (IC50: 1 microg ml(-1)) as compared to seeds (6 microg ml(-1)). In addition, cardoon leaves were efficient to inhibit growth of pathogenic bacteria mainly against Staphylococcus aureus and Escherichia coli. The identification of phenolic compounds from leaves revealed that syringic and trans-cinnamic acids were the major molecules. 相似文献