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排序方式: 共有153条查询结果,搜索用时 15 毫秒
61.
Annabi A Kessabi K Kerkeni A Said K Messaoudi I 《Biological trace element research》2012,148(3):345-355
This study aims to investigate the effect of cadmium (Cd) exposure on growth and fecundity of mosquitofish Gambusia affinis. For this purpose, two natural populations of pregnant females of G. affinis captured from two sites were differently contaminated with Cd (S1 present Cd levels 5-fold higher than S2) and a sublethal exposure to 0.4 mg CdCl(2)/L (10% of LC(50)) during 56 days was conducted in vivo. The length-weight regression revealed a significant difference in the growth between these two populations. A significant difference in fecundity was also noted between the two populations. Indeed, the embryo numbers in pregnant females captured from S1 are significantly higher than those noted in pregnant females from S2 (21.17±5 and 7.97±2.12, respectively; p<0.05). Following Cd exposure, we noted a growth perturbation resulting in lower values of both indices BWG and SGR following 7 and 21 days (-5.21 and -1.18 for BWG, and -2.09 and -0.46 for SGR, respectively) and a recuperation of growing weight at 42 and 56 days (1.32 and 1.71 for BWG, and 0.45 and 0.54 for SGR, respectively). For CF index, we observed a significant difference (p<0.05) between control and Cd groups at 7 and 21 days of exposure, and at 21 and 56 days respectively for HSI and GSI indices. Furthermore, Cd contents in both tissues (liver and yolk sac) and fractions (cytosolic and membrane) are significantly different between groups during experimentation. In addition, the Cd contents noticed in the liver membrane fraction are significantly higher than those noted in the yolk sac tissue. The MTs levels revealed a significant difference between the control and Cd groups. In liver tissue, a significant difference was noted, in MTs levels, during the Cd exposure (7, 21, 42, and 56 days) while in the yolk sac tissue the difference was noted at 42 days of exposure. Taken together, these results imply the potential negative effect of Cd on physiological status of G. affinis as evidenced by decreasing growth and fecundity rate. 相似文献
62.
Amor-Guéret M Dubois-d'Enghien C Laugé A Onclercq-Delic R Barakat A Chadli E Bousfiha AA Benjelloun M Flori E Doray B Laugel V Lourenço MT Gonçalves R Sousa S Couturier J Stoppa-Lyonnet D 《Genetic testing》2008,12(2):257-261
Bloom's syndrome (BS) is a rare autosomal recessive disease predisposing patients to all types of cancers affecting the general population. BS cells display a high level of genetic instability, including a 10-fold increase in the rate of sister chromatid exchanges, currently the only objective criterion for BS diagnosis. We have developed a method for screening the BLM gene for mutations based on direct genomic DNA sequencing. A questionnaire based on clinical information, cytogenetic features, and family history was addressed to physicians prescribing BS genetic screening, with the aim of confirming or guiding diagnosis. We report here four BLM gene mutations, three of which have not been described before. Three of the mutations are frameshift mutations, and the fourth is a nonsense mutation. All these mutations introduce a stop codon, and may therefore be considered to have deleterious biological effect. This approach should make it possible to identify new mutations and to correlate them with clinical information. 相似文献
63.
Rafik?Menacer Abdelghani?May Lotfi?BelkhiriEmail author Abdelhamid?Mousser 《Journal of molecular modeling》2017,23(12):358
The nature of the chemical metal–metal bond in M2(CO)10 (M?=?Mn, Re, Tc) dinuclear decacarbonyls complexes was investigated for the first time using the natural orbital chemical valence (NOCV) approach combined with the extended transition state (ETS) for energy decomposition analysis (EDA). The optimized geometries carried out at different levels of theory BP86, BLYP, BLYPD and BP86D, showed that the latter method, i.e., BP86D, led to the best agreement with X-ray experimental measurements. The BP86D/TZP results revealed that the computed covalent contribution to the metal–metal bond are 60.5%, 54.1% and 52.0% for Mn–Mn, Re–Re and Tc–Tc, respectively. The computed total interaction energies resulting from attractive terms (ΔE orb and ΔE eles), correspond well to experimental predictions, based on bond lengths and energy interaction analysis for the studied complexes. 相似文献
64.
Abdelhamid Liacini Judith Sylvester Wen Qing Li Muhammad Zafarullah 《Matrix biology》2002,21(3):251-262
65.
Abdelhamid Mtioui Lucienne Gourdoux Bernard Fournier Robert Moreau 《Archives of insect biochemistry and physiology》1993,24(3):113-128
In vitro hormonally induced variations of glucose catabolism in mealworm fat body tissue were examined by a microradiorespirometric method. An insulin-like peptide (ILP) extracted from the midgut of last larval instar mealworm larvae significantly modified glucose catabolism and was dependent on energy metabolism and on the Ca2+ concentration in the culture medium. Using two different labelled substrate molecules, the stimulatory effects of ILP (compared with those of mammalian insulin) on the relative use of the pentose cycle as opposed to the glycolytic-citric acid cycle by the mealworm fat body were measured in vitro. Metabolic variations were evaluated using either [1-14C]glucose or [6-14C]glucose as substrates. Time course and dose-response curves of ILP and the hormonally induced variations in total CO2 and 14CO2 kinetics were determined. Modification in the specific radioactivity kinetics of 14CO2 derived from [1-14C] glucose and [6-14C] glucose molecules under hormonal effects were observed. As demonstrated in in vivo studies, ILP stimulated the relative utilization of the pentose cycle. However, this effect was observed much more rapidly, but for a shorter time, with fat body in vitro. Mammalian insulin produced similar, but not identical effects. Variations in transmembranous Ca2+ cellular exchanges, induced by either EGTA, nifedipine, or calcium ionophore ionomycin included in the culture medium, indicated that the stimulatory effects of ILP depends on this cation. © 1993 Wiley-Liss, Inc. 相似文献
66.
18,19-Dihydroxycorticosterone (18,19(OH)2-B) and 18-hydroxy-19-norcorticosterone (18-OH-19-nor-B) measurements were carried out on the urine of patients with primary aldosteronism (PA), essential hypertension (EHT), and liver cirrhosis with (LC, SA (+)) and without (LC, SA (-)) aldosteronism. The separation of these steroids was performed by extraction and high-performance liquid chromatography followed by radioimmunoassay (RIA) with specific antibodies prepared in our laboratory. 18,19(OH)2-B excretion was elevated in patients with PA (24 +/- 5.9 [+/- SE] micrograms/24 hr; n = 15) and LC, SA (+) (83 +/- 9.4 micrograms/24 hr; n = 8). Values in LC, SA (-) (3.1 +/- 1.2 micrograms/24 hr; n = 8) and in EHT (3.7 +/- 0.4 micrograms/24 hr; n = 42) were found to be similar to those in normal subjects (5.5 +/- 0.9 micrograms/24 hr; n = 30). The values of urinary 18-OH-19-nor-B in PA and LC, SA (+) were higher than in LC, SA (-) EHT and normal subjects (P less than 0.05). Values in the latter three groups, as compared with each other, did not show significant alterations. Nothing is known about the biologic relevance of 18,19(OH)2-B and very little about that of 18-OH-19-nor-B, but the latter steroid seems to potentiate experimental renal hypertension. One can speculate about possible roles of both steroids as precursors of other steroids, e.g., the biologically potent mineralocorticoid 19-noraldosterone. The data obtained suggest that it is not relevant to measure the urinary levels of either steroid in these clinical syndromes. 相似文献
67.
68.
Rim?Tinhinen?Maougal Adnane?Bargaz Charaf?Sahel Laurie?Amenc Abdelhamid?Djekoun Claude?Plassard Jean-Jacques?DrevonEmail author 《Planta》2014,239(4):901-908
Soil organic phosphorus (Po) such as phytate, which comprises up to 80 % of total Po, must be hydrolyzed by specific enzymes called phytases to be used by plants. In contrast to plants, bacteria, such as Bacillus subtilis, have the ability to use phytate as the sole source of P due to the excretion of a beta-propeller phytase (BPP). In order to assess whether the B. subtilis BPP could make P available from phytate for the benefit of a nodulated legume, the P-sensitive recombinant inbred line RIL147 of Phaseolus vulgaris was grown under hydroaeroponic conditions with either 12.5 μM phytate (C6H18O24P6) or 75 μmol Pi (K2HPO4), and inoculated with Rhizobium tropici CIAT899 alone, or co-inoculated with both B. subtilis DSM 10 and CIAT899. The in situ RT-PCR of BPP genes displayed the most intense fluorescent BPP signal on root tips. Some BPP signal was found inside the root cortex and the endorhizosphere of the root tip, suggesting endophytic bacteria expressing BPP. However, the co-inoculation with B. subtilis was associated with a decrease in plant P content, nodulation and the subsequent plant growth. Such a competitive effect of B. subtilis on P acquisition from phytate in symbiotic nitrogen fixation might be circumvented if the rate of inoculation were reasoned in order to avoid the inhibition of nodulation by excess B. subtilis proliferation. It is concluded that B. subtilis BPP gene is expressed in P. vulgaris rhizosphere. 相似文献
69.
70.
Wiart J Hadjem A Varsier N Conil E 《Progress in biophysics and molecular biology》2011,107(3):421-427
Children are more and more using wireless communication systems. This growth has strengthened public concern and has highlighted the need to assess the radio frequency (RF) exposure of children. In dosimetry, taking advantage of the improvement of High Performance Calculation systems, great efforts have been carried out to improve the numerical tools and human models used to assess the Specific Absorption Rate (SAR). This paper analyses progress in building child and foetus models for numerical dosimetry purpose. The simulation results, in terms of Specific Absorption Rate over 1 and 10 g of tissues, in specific organs such as brain and averaged over the whole body, are reported and analysed. The results show that compliance methods used nowadays to certify phones are valid for children. The studies also show that specific tissues such as peripheral brain tissues can have higher exposure with children than with adults. Studies performed with plane waves as sources and whole body children models show that the whole body SAR of children can be higher than the WBSAR of adults and that the compliance to ICNIRP reference levels does not guarantee the compliance to ICNIRP basic restrictions. Dealing with the foetus models and dielectric properties great efforts have been made. Preliminary results show that the foetus exposure is often lower than the mother exposure, with an important influencing parameter: the foetus position in the uterus. 相似文献