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21.
Hafedh Hajlaoui Najla Trabelsi Emira Noumi Mejdi Snoussi Hanen Fallah Riadh Ksouri Amina Bakhrouf 《World journal of microbiology & biotechnology》2009,25(12):2227-2238
The composition of the essential oils and methanolic extracts of two cultivated mint species (M. longifolia and M. pulegium), as well as the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract of Mentha longifolia and Mentha pulegium were compared. GC-MS analysis of the essential oil identified 41 compounds constituting 96.66 and 96.13% of the total oil
from M. longifolia and M. pulegium, respectively. The later oils were rich on pulegone (47.15 and 61.11%, respectively). Moreover, 1,8 cineole (11.54%), menthone
(10.7%), α-pinene (3.57%), α-terpineol (3.17%) and d-cadinene (3.53%) were only present in M. longifolia oil, while isomenthone (17.02%), and piperitone (2.63%), were characteristic of M. pulegium oil. Shoot extract of the two species showed significantly different contents in total polyphenols (89.1 and 37.41 mg GAE/g
DW), flavonoids (63.93 and 33.83 mg CE/g DW) and tannins (1.47 and 3.07 mg CE/g DW), respectively in M. longifolia and M. pulegium. The essential oils showed strong antimicrobial activity against all 16 microorganisms tested, whereas the methanol extracts
were inactive. Moreover, the essential oils showed higher antioxidant activity than the methanolic extracts against the DPPH
and superoxide radical scavenging. In fact, antioxidant activities of the oils were the same for both M. longifolia and M. pulegium against DPPH (IC50 = 9 and 10 μg/ml, respectively) and 2-fold and 4-fold higher than shoot extracts (IC50 = 20 and 48 μg/ml, respectively). Moreover, both oils showed the same antioxidative abilities as compared to the positive
control (butylated hydroxytoluene). In the same way, the capacity to inhibit superoxide anion was very significant for the
two oils (0.1 μg/ml for M. longifolia and 0.11 μg/ml for M. pulegium). 相似文献
22.
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
23.
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
24.
Antioxidant defense responses: physiological plasticity in higher plants under abiotic constraints 总被引:4,自引:0,他引:4
Cheruth Abdul Jaleel Ksouri Riadh Ragupathi Gopi Paramasivam Manivannan Jallali Inès Hameed Jasim Al-Juburi Zhao Chang-Xing Shao Hong-Bo Rajaram Panneerselvam 《Acta Physiologiae Plantarum》2009,31(3):427-436
Environmental stresses (salinity, drought, heat/cold, light and other hostile conditions) may trigger in plants oxidative
stress, generating the formation of reactive oxygen species (ROS). These species are partially reduced or activated derivatives
of oxygen, comprising both free radical and non-radical (H2O2) forms, leading to cellular damage, metabolic disorders and senescence processes. In order to overcome oxidative stress,
plants have developed two main antioxidants defense mechanisms that can be classified as non-enzymatic and enzymatic systems.
The first class (non-enzymatic) consists of small molecules such as vitamin (A, C and E), glutathione, carotenoids and phenolics
that can react directly with the ROS by scavenging them. Second class is represented by enzymes among them superoxide dismutase,
peroxidase and catalase which have the capacity to eliminate superoxide and hydrogen peroxide. In this review, we have tried
to explore the related works, which have revealed the changes in the basic antioxidant metabolism of plants under various
abiotic constraints. 相似文献
25.
Abdelmajid Zouhir Riadh Hammami Ismail Fliss Jeannette Ben Hamida 《The protein journal》2010,29(6):432-439
Bacteriocins are ribosomally-synthesized peptides or proteins produced by a wide range of bacteria. The antimicrobial activity
of this group of natural substances against foodborne pathogenic and spoilage bacteria has raised considerable interest for
their application in food preservation. Classifying these bacteriocins in well defined classes according to their biochemical
properties is a major step towards characterizing these anti-infective peptides and understanding their mode of action. Actually,
the chosen criteria for bacteriocins’ classification lack consistency and coherence. So, various classification schemes of
bacteriocins resulted various levels of contradiction and sorting inefficiencies leading to bacteriocins belonging to more
than one class at the same time and to a general lack of classification of many bacteriocins. Establishing a coherent and
adequate classification scheme for these bacteriocins is sought after by several researchers in the field. It is not straightforward
to formulate an efficient classification scheme that encompasses all of the existing bacteriocins. In the light of the structural
data, here we revisit the previously proposed contradictory classification and we define new structure-based sequence fingerprints
that support a subdivision of the bacteriocins into 12 groups. The paper lays down a resourceful and consistent classification
approach that resulted in classifying more than 70% of bacteriocins known to date and with potential to identify distinct
classes for the remaining unclassified bacteriocins. Identified groups are characterized by the presence of highly conserved
short amino acid motifs. Furthermore, unclassified bacteriocins are expected to form an identified group when there will be
sufficient sequences. 相似文献
26.
Plants are frequently submitted to iron deficiency when growing on calcareous soils, which contain high concentrations of bicarbonate. The purpose of this study was to investigate the variability of physiological responses of Tunisian grapevine varieties to bicarbonate-induced iron chlorosis. Vine woodcuttings of seven autochthonous Tunisian varieties (Khamri, Mahdaoui, Blan3, Saouadi, Arich Dressé, Beldi and Balta4), two rootstocks (140Ru and S.O.4), and an introduced table variety (Cardinal) were cultivated on inert sand for 2 months using a complete nutrient solution (20 microM Fe) that was either well supplied or not supplied with 10 mM HCO3-. Young leaves of plants cultivated on bicarbonate-enriched medium showed characteristic symptoms of iron chlorosis, although the intensity of the symptoms depended on the variety and the rootstock. Chlorosis score confirmed these observations since the most sensitive varieties showed the highest values. This variability in tolerance to iron deficiency was also displayed when analysing the physiological parameters (shoot length, plant dry weight, and chlorophyll concentration) and the iron contents in the 4th leaf. Analysis of morphological and physiological parameters showed three behaviour groups. The first one corresponded to tolerant varieties (Khamri, Mahdaoui, and the root-stock: 140Ru), the second included moderately tolerant vines (Saouadi, Arich Dressé, Blanc3, and the rootstock: S.O.4) and the third represented the sensitive ones (Balta4, Beldi, and Cardinal). 相似文献
27.
Clusters of charged residues are one of the key features of protein primary structure since they have been associated to important functions of proteins. Here, we present a proteome wide scan for the occurrence of Charge Clusters in Protein sequences using a new search tool (FCCP) based on a score‐based methodology. The FCCP was run to search charge clusters in seven eukaryotic proteomes: Arabidopsis thaliana, Caenorhabditis elegans, Danio rerio, Drosophila melanogaster, Homo sapiens, Mus musculus, and Saccharomyces cerevisiae. We found that negative charge clusters (NCCs) are three to four times more frequent than positive charge clusters (PCCs). The Drosophila proteome is on average the most charged, whereas the human proteome is the least charged. Only 3 to 8% of the studied protein sequences have negative charge clusters, while 1.6 to 3% having PCCs and only 0.07 to 0.6% have both types of clusters. NCCs are localized predominantly in the N‐terminal and C‐terminal domains, while PCCs tend to be localized within the functional domains of the protein sequences. Furthermore, the gene ontology classification revealed that the protein sequences with negative and PCCs are mainly binding proteins. Proteins 2015; 83:1252–1261. © 2015 Wiley Periodicals, Inc. 相似文献
28.
Younés Hachana Helmi Chaabène Ghada Ben Rajeb Riadh Khlifa Ridha Aouadi Karim Chamari Tim J. Gabbett 《PloS one》2014,9(4)
Background
Agility is a determinant component in soccer performance. This study aimed to evaluate the reliability and sensitivity of a “Modified Illinois change of direction test” (MICODT) in ninety-five U-14 soccer players.Methods
A total of 95 U-14 soccer players (mean ± SD: age: 13.61±1.04 years; body mass: 30.52±4.54 kg; height: 1.57±0.1 m) from a professional and semi-professional soccer academy, participated to this study. Sixty of them took part in reliability analysis and thirty-two in sensitivity analysis.Results
The intraclass correlation coefficient (ICC) that aims to assess relative reliability of the MICODT was of 0.99, and its standard error of measurement (SEM) for absolute reliability was <5% (1.24%). The MICODT’s capacity to detect change is “good”, it’s SEM (0.10 s) was ≤ SWC (0.33 s). The MICODT is significantly correlated to the Illinois change of direction speed test (ICODT) (r = 0.77; p<0.0001). The ICODT’s MDC95 (0.64 s) was twice about the MICODT’s MDC95 (0.28 s), indicating that MICODT presents better ability to detect true changes than ICODT. The MICODT provided good sensitivity since elite U-14 soccer players were better than non-elite one on MICODT (p = 0.005; dz = 1.01 [large]). This was supported by an area under the ROC curve of 0.77 (CI 95%, 0.59 to 0.89, p<0.0008). The difference observed in these two groups in ICODT was not statistically significant (p = 0.14; dz = 0.51 [small]), showing poor discriminant ability.Conclusion
MICODT can be considered as more suitable protocol for assessing agility performance level than ICODT in U-14 soccer players. 相似文献29.
Mondher Boulaaba Soninkhishig Tsolmon Riadh Ksouri Junkyu Han Kiyokazu Kawada Abderrazak Smaoui Chedly Abdelly Hiroko Isoda 《Cytotechnology》2013,65(6):927-936
Taking into account that oxidative stress is among the factors causing cancer-related death; chemoprevention which consists in using antioxidant substances such as phenolics could prevent cancer formation and progression. In the present study, phenolic contents and antioxidant activities of methanolic extracts from the halophyte Tamarix gallica shoots were determined. Moreover, the anticancer effect of this species on human colon cancer cells and the likely underlying mechanisms were also investigated. Shoot extracts showed an appreciable total phenolic content (85 mg GAE/g DW) and a high antioxidant activity (IC50 = 3.3 μg/ml for DPPH test). At 50 and 100 μg/ml, shoot, leaf, and flower extracts significantly inhibited Caco-2 cell growth. For instance, almost all plant part extracts inhibited cell growth by 62 % at the concentration 100 μg/ml. DAPI staining results revealed that these extracts decrease DNA synthesis and confirm their effect on Caco-2 cells proliferation, principally at 100 μg/ml. More importantly, cell mitosis was arrested at G2/M phase. The changes in the cell-cycle-associated proteins (cyclin B1, p38, Erk1/2, Chk1, and Chk2) are correlated with the changes in cell cycle distribution. Taken together, our data suggest that T. gallica is a promising candidate species to be used as a source of anticancer biomolecules. 相似文献
30.
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