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Touhami A Othmane A Ouerghi O Ouada HB Fretigny C Jaffrezic-Renault N 《Biomolecular engineering》2002,19(2-6):189-193
In the present study the atomic force microscope (AFM) was used to image the surface morphology of red blood cells (RBC) for the first time. The AFM yielded very reproducible images without appreciable modifications of the sample surfaces. In addition to this topographical imaging, we have developed an experimental approach to measure the binding strength between antibody (anti-A), and the RBC antigen A, when reversible bonds between specific molecules such as antigen and antibody mediate the adhesion. The experimental results suggest that the procedure established here may be used for specific antibody detection. This study has also enhanced our understanding under physiological conditions of molecular interaction in particular antigen-antibody. 相似文献
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Large, rapidly evolving intergenic spacers in the mitochondrial DNA of the salamander family Ambystomatidae (Amphibia: Caudata) 总被引:5,自引:2,他引:3
We report the presence, in the mitochondrial DNA (mtDNA) of all of the
sexual species of the salamander family Ambystomatidae, of a shared 240- bp
intergenic spacer between tRNAThr and tRNAPro. We place the intergenic
spacer in context by presenting the sequence of 1,746 bp of mtDNA from
Ambystoma tigrinum tigrinum, describe the nucleotide composition of the
intergenic spacer in all of the species of Ambystomatidae, and compare it
to other coding and noncoding regions of Ambystoma and several other
vertebrate mtDNAs. The nucleotide substitution rate of the intergenic
spacer is approximately three times faster than the substitution rate of
the control region, as shown by comparisons among six Ambystoma
macrodactylum sequences and eight members of the Ambystoma tigrinum
complex. We also found additional inserts within the intergenic spacers of
five species that varied from 87-444 bp in length. The presence of the
intergenic spacer in all sexual species of Ambystomatidae suggests that it
arose at least 20 MYA and has been a stable component of the ambystomatid
mtDNA ever since. As such, it represents one of the few examples of a large
and persistent intergenic spacer in the mtDNA of any vertebrate clade.
相似文献
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Imene Chentir Amel Doumandji Jihene Ammar Fatma Zili Mourad Jridi Giorgos Markou Hatem Ben Ouada 《Journal of applied phycology》2018,30(3):1563-1574
The interactive effects of light intensity, NaCl, nitrogen, and phosphorus on intracellular biomass content and extracellular polymeric substance production were assessed for Arthrospira sp. (Spirulina) in a two-phase culture process using principal component analysis and central composite face design. Under high light intensity (120 μmol photons m?2?s?1) and low NaCl (1 gL?1), NaNO3, and K2HPO4 (0.5 g L?1), the carbohydrate content was maximized to 26.61%. Interaction of both K2HPO4 (1.6 gL?1) and NaCl (1.19 gL?1) with low NaNO3 (0.5 gL?1) achieved the maximum content of lipids (15.62%), while high NaCl (40 gL?1), K2HPO4, and NaNO3 (4.5 gL?1) enhanced mainly total carotenoids (0.85%). Conversely, under low light intensity of 10 μmol photons m?2?s?1 combined with 11.76 gL?1 of NaCl, 0.5 gL?1 of NaNO3, and 2.68 gL?1 of K2HPO4, the phycobiliprotein content reached its highest level (16.09%). The maximum extracellular polymeric substance (EPS) production (0.902 gg?1?DW) was triggered under moderate light of 57.25 μmol photons m?2?s?1 and interaction of high NaCl (40 gL?1) and K2HPO4 (4.5 gL?1) with low NaNO3 (0.5 gL?1). The maximization ratios of intracellular biomass content in terms of carbohydrate, lipid, total carotenoid, phycobiliprotein, and EPS production were 3.55-, 1.73-, 9.55-, 2.92-, and 1.46-fold, respectively, greater than those obtained at optimal growth conditions. This study demonstrated that the multiple stress factors applied to the adopted two-phase culture process could be a promising strategy to produce biomass enriched in various high-value compound. 相似文献
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Lamia Trabelsi Hatem Ben Ouada Hassen Bacha Mohamed Ghoul 《Journal of applied phycology》2009,21(4):405-412
The effects of light intensity and temperature on Arthrospira platensis growth and production of extracellular polymeric substances (EPS) in batch culture were evaluated using a three-level, full-factorial
design and response surface methodology. Three levels were tested for each parameter (temperature: 30, 35, 40°C; light intensity:
50, 115, 180 μmol photons m−2 s−1). Both growth and EPS production are influenced mainly by the temperature factor but the interaction term temperature*light
intensity also had a significant effect. In addition, conditions optimising EPS production are different from those optimising
growth. The highest growth rate (0.414 ± 0.003 day−1) was found at the lowest temperature (30°C) and highest light intensity (180 μmol photons m−2 s−1) tested, no optima were detectable within the given test range. Obviously, optima for growth must be at a temperature lower
than 30°C and a light intensity higher than 180 μmol photons m−2 s−1. For EPS production, light intensity had a positive linear effect (optimum obviously higher than 180 μmol photons m−2 s−1), but for the temperature parameter a maximum effect was detectable at 35°C. 相似文献
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A simple, fast and sensitive method was developed to verify the presence of
the sialyl Lewis(x) antigen on an N-linked glycoprotein. High performance
liquid chromatography-electrospray mass spectrometry (HPLC-ESI/MS) was used
to identify which of the five N-linked glycosylation sites of human plasma
alpha1-acid-glycoprotein (orosomucoid, OMD) contain the sialyl Lewis(x)
antigen. OMD was digested with proteolytic enzymes and analyzed by reversed
phase chromatography coupled with on-line ESI/MS. A tandem mass
spectrometry experiment was designed to detect the presence of the sialyl
Lewis(x) antigen based on the observation of an 803 mass to charge ratio (
m/z ) ion produced in the intermediate pressure region of the ESI
interface. The ESI/MS signal at m/z 803 is consistent with an oxonium ion
for a glycan structure containing NeuAc, Gal, GlcNAc, and Fuc. The identity
of the m/z 803 ion was confirmed by ESI/MS/MS analysis of the m/z 803
fragment ion and comparison with a sialyl Lewis(x) standard. The
stereochemistry and linkage positions were assigned using previous NMR
analysis but could be determined with permethylation analysis if necessary.
The analysis of OMD gave a pattern showing signal for the sialyl Lewis(x)
antigen coeluting with each of the five N-linked glycopeptides. The ability
to monitor sialyl Lewis(x) expression at each of the five sites is of
interest in the study of OMD's role in inflammatory diseases.
相似文献
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Ben Dhiab Rym Ghenim Nejeh Trabelsi Lamia Yahia Ali Challouf Rafika Ghozzi Khemissa Ammar Jihene Omrane Hela Ben Ouada Hatem 《Journal of applied phycology》2010,22(6):745-752
Combined effect of light intensity and glucose concentration on Arthrospira platensis growth and photosynthetic response was evaluated using a 32 factorial design. This design was carried out with light levels of 50, 100, and 150 μmol photons m−2 s−1 and glucose concentrations of 0.5, 1.5, and 2.5 g L−1. Results from the response surface methodology were that the highest level of light intensity and glucose concentration improved
biomass (1.33 g L−1), maximum specific growth rate (0.49 day−1), and net photosynthetic rate (139.89 μmol O2 mg Chl−1 h−1). Furthermore, the interaction of both factors showed that at low light, glucose had a low effect on maximum biomass and
maximal net photosynthetic rate. However, at the highest light levels, the effect of glucose was more sensitive and the increase
of glucose concentration increased the levels of all responses. The rates of the instantaneous relative growth, net photosynthesis,
and dark respiration of growth cultures showed two different phases in mixotrophic condition. The first was distinguished
by the preponderance of the photoautotrophic mode; the second was based mainly on photoheterotrophy. 相似文献
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Osorio-Córdoba J LL Rodriguez-Verástegui F Díaz de León-Sánchez E Bosquez-Molina JR Verde-Calvo HB Escalona-Buendía LJ Pérez-F lores C Pelayo-Zaldívar 《Phyton》2015,84(2):375-384
Cactus stems, the cladodes of Opuntia spp. cacti, are consumed in Mexico and other countries due to their fresh and herbaceous flavor, and because of their widely known nutraceutical benefits. In order to extend the postharvest life of this vegetable, the effect of a modified atmosphere packaging (MAP) was studied in cactus stems of the cultivar Atlixco stored at 4 ± 1 °C for 20 days under three types of atmospheres: (1) air (passive atmosphere), (2) 5 kPa O2 + 4 kPa CO2, and (3) N2. During storage, the titratable acidity decreased and the color of cladodes became darker and less green; however, the 5 kPa O2 + 4 kPa CO2 atmosphere was able to preserve both quality characteristics. All modified atmospheres reduced weight loss (from 8 to <2%) and the symptoms of chilling injury, and this physiological disorder appeared earlier in controls than in MAP-stored cladodes. The levels of fermentation metabolites were low in all three evaluated atmospheres. Because of this, only cladodes stored under the N2 atmosphere were selected for furthersensory analysis of the MAP effect on odor perception as evaluated by a trained panel. Results indicated that there was no detrimental effect (atypical odors) of MAP on this sensory characteristic. We conclude that cultivar Atlixco is suitable for preservation using MAP technology. 相似文献
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Survival of vegetation on soil-capped mining wastes is often impaired during dry seasons due to the limited amount of water stored in the shallow soil capping. Growth and survival of Rhodes grass (Chloris gayana) during soil drying on various layered capping sequences constructed of combinations of topsoil, subsoil, seawater-neutralised residue sand and low grade bauxite was determined in a glasshouse. The aim was to describe the survival of Rhodes grass in terms of plant and soil water relationships. The soil water characteristic curve and soil texture analysis was a good predictor of plant survival. The combination of soil with a high water holding capacity and low soil water diffusivity (e.g. subsoil with high clay contents) with soil having a high water holding capacity and high diffusivity (e.g. residue sand) gave best survival during drying down (up to 88 days without water), whereas topsoil and low grade bauxite were unsuitable (plants died within 18–39 days). Clayey soil improved plant survival by triggering a water stress response during peak evaporative water demand once residue sand dried down and its diffusivity fell below a critical range. Thus, for revegetation in seasonally dry climates, soil capping should combine one soil with low diffusivity and one or more soils with high total water holding capacity and high diffusivity. 相似文献