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Essential oil of the leaves of Ricinus communis L.: In vitro cytotoxicity and antimicrobial properties
Zarai Zied,Chobba Ines,Mansour Riadh,Békir Ahmed
Lipids in Health and Disease , 2012, DOI: 10.1186/1476-511x-11-102
Abstract: Background The aim of the present study was to appraise the antimicrobial activity of Ricinus communis L. essential oil against different pathogenic microorganisms and the cytotoxic activity against HeLa cell lines. Methods The agar disk diffusion method was used to study the antibacterial activity of Ricinus communis L. essential oil against 12 bacterial and 4 fungi strains. The disc diameters of zone of inhibition (DD), the minimum inhibitory concentrations (MIC) and the concentration inhibiting 50% (IC50) were investigated to characterize the antimicrobial activities of this essential oil. The in vitro cytotoxicity of Ricinus communis L. essential oil was examined using a modified MTT assay; the viability and the IC50 were used to evaluate this test. Results The essential oil from the leaves of Ricinus communis L. was analyzed by GC–MS and bioassays were carried out. Five constituents of the oil were identified by GC–MS. The antimicrobial activity of the oil was investigated in order to evaluate its efficacy against twelve bacteria and four fungi species, using disc diffusion and minimum inhibitory concentration methods. The essential oil showed strong antimicrobial activity against all microorganisms tested with higher sensitivity for Bacillus subtilis, Staphylococcus aureus and Enterobacter cloacae. The cytotoxic and apoptotic effects of the essential oil on HeLa cell lines were examined by MTT assay. The cytotoxicity of the oil was quite strong with IC50 values less than 2.63 mg/ml for both cell lines. Conclusion The present study showed the potential antimicrobial and anticarcinogenic properties of the essential oil of Ricinus communis L., indicating the possibilities of its potential use in the formula of natural remedies for the topical treatment of infections.
Immunohistochemical localization of hepatopancreatic phospholipase in gastropods mollusc, Littorina littorea and Buccinum undatum digestive cells
Zied Zarai, Nicholas Boulais, Pascale Marcorelles, Eric Gobin, Sofiane Bezzine, Hafedh Mejdoub, Youssef Gargouri
Lipids in Health and Disease , 2011, DOI: 10.1186/1476-511x-10-219
Abstract: We have previously producted an antiserum reacting specifically with mSDPLA2. It labeled zymogen granules of the hepatopancreatic acinar cells and the secretory materials of certain epithelial cells in the depths of epithelial crypts in the hepatopancreas of snail. To confirm this localization a laser capture microdissection was performed targeting stained cells of hepatopancreas tissue sections. A Western blot analysis revealed a strong signal at the expected size (30 kDa), probably corresponding to the PLA2.The present results support the presence of two hepatopancreatic intracellular and extracellular PLA2 in the prosobranchs gastropods molluscs, Littorina littorea and Buccinum undatum and bring insights on their localizations.Snails require lipids for metabolic energy and for maintaining the structure and integrity of cell membranes in common with other animals to tolerate environemental strains [1]. The analyses of lipid composition of digestive gland and pedal muscle of two northern freshwater pulmonate snails Lymnaea stagnalis and Lymnaea ovata and three marine prosobranch gastropods Littorina obtusata, Littorina littorea and Buccinum undatum from the White Sea, shown that the content of triacylglycerides both in digestive gland and pedal was higher in littoral dwellers Littorina, the activity of which depends on the tide level. The presence of massive shell enhances demands in energy needed for supporting movement and activity. Because the intensity of energy metabolism is related to quantity of total phospholipids, mitochondria and activity of their oxidizing ferments, the presence of thick shell in marine snails together with motor activity costs more in terms of energy than in freshwater snails with thin shell [1].In different molluscs, food is processed to varying degrees as it passes through the alimentary tract. It is generally assumed that digestion of ingested material takes place in two phases, an extracellular process and intracellular digestion, w
Immunohistochemical localization of hepatopancreatic phospholipase A2 in Hexaplex Trunculus digestive cells
Zied Zarai, Nicholas Boulais, Aida Karray, Laurent Misery, Sofiane Bezzine, Tarek Rebai, Youssef Gargouri, Hafedh Mejdoub
Lipids in Health and Disease , 2011, DOI: 10.1186/1476-511x-10-91
Abstract: The marine snail digestive phospholipase A2 (mSDPLA2) has been previously purified from snail hepatopancreas. The specific polyclonal antibodies were prepared and used for immunohistochimical and immunofluorescence analysis in order to determine the cellular location of mSDPLA2. Our results showed essentially that mSDPLA2 was detected inside in specific vesicles tentatively named (mSDPLA2+) granules of the digestive cells. No immunolabelling was observed in secretory zymogene-like cells. This immunocytolocalization indicates that lipid digestion in the snail might occur in specific granules inside the digestive cells.The cellular location of mSDPLA2 suggests that intracellular phospholipids digestion, like other food components digestion of snail diet, occurs in these digestive cells. The hepatopancreas of H. trunculus has been pointed out as the main region for digestion, absorption and storage of lipids.The Muricidae family of snails includes about 1,000 species, which represent a diverse and important component of marine communities [1]. The banded murex, Hexaplex trunculus (Linnaeus, 1758), is found in the mediterranean sea and adjacent atlantic ocean from the Portuguese coast, southward to Morocco and to the Madeira and Canary islands [2] and [3]. This specie is a commercially important marine snail in the mediterranean coasts.The digestive gland or the hepatopancreas of gastropod molluscs like the marine snail H. trunculus is the key organ for metabolism. It is the main source of production of digestive enzymes, and it is involved in absorption of nutrients, food storage and excretion [4]. It combines many functions of the liver, pancreas, intestine and other organs in vertebrates [5]. For this reason, it has captivated scientists for more than 180 years [6] and [7] and it was considered as an excellent model for food digestion and cell secretion [8]. Its primary role is the synthesis and secretion of digestive enzymes, swallowing and final digestion of the in
The in-vitro evaluation of antibacterial, antifungal and cytotoxic properties of Marrubium vulgare L. essential oil grown in Tunisia
Zied Zarai, Adel Kadri, Ines Ben Chobba, Riadh Ben Mansour, Ahmed Bekir, Hafedh Mejdoub, Néji Gharsallah
Lipids in Health and Disease , 2011, DOI: 10.1186/1476-511x-10-161
Abstract: The agar disk diffusion method was used to study the antibacterial activity of M. vulgare essential oil against 12 bacterial and 4 fungi strains. The disc diameters of zone of inhibition (DD), the minimum inhibitory concentrations (MIC) and the concentration inhibiting 50% (IC50) were investigated to characterize the antimicrobial activities of this essential oil. The in vitro cytotoxicity of M. vulgare essential oil was examined using a modified MTT assay; the viability and the IC50 were used to evaluate this test.The antimicrobial activity of the essential oil was investigated in order to evaluate its efficacy against the different tested microorganisms. The present results results showed a significant activity against microorganisms especially Gram (+) bacteria with inhibition zones and minimal inhibitory concentration values in the range of 6.6-25.2 mm and 1120-2600 μg/ml, respectively, whereas Gram (-) bacteria exhibited a higher resistance. As far as the antifungal activity, among four strains tested, Botrytis cinerea exhibited the strongest activity with inhibition zones of 12.6 mm. However, Fusarium solani, Penicillium digitatum and Aspergillus niger were less sensitive to M. vulgare essential oil. About the citotoxicity assay, this finding indicate the capability of this essential oil to inhibited the proliferation of HeLa cell lines under some conditions with IC50 value of 0.258 μg/ml.This investigation showed that the M. vulgare essential oil has a potent antimicrobial activity against some Gram (+) pathogenic bacteria and Botrytis cinerea fungi. The present studies confirm the use of this essential oil as anticancer agent. Further research is required to evaluate the practical values of therapeutic applications.The Lamiaceae plants was considered as one of the large plant families used as a framework to evaluate the occurrence of typical secondary metabolites [1]. The genus Marrubium comprises 10 species, which are found wild in many regions of Tunisia.
Characterization of the cubic exponential families by orthogonality of polynomials
Abdelhamid Hassairi,Mohammed Zarai
Mathematics , 2004, DOI: 10.1214/009117904000000522
Abstract: This paper introduces a notion of 2-orthogonality for a sequence of polynomials to give extended versions of the Meixner and Feinsilver characterization results based on orthogonal polynomials. These new versions subsume the Letac-Mora characterization of the real natural exponential families having cubic variance function.
On the Structure of the Initiation and Elongation Rates that Maximize Protein Production in the Ribosome Flow Model
Yoram Zarai,Michael Margaliot
Quantitative Biology , 2014,
Abstract: Translation is a crucial step in gene expression. During translation, macromolecules called ribosomes "read" the mRNA strand in a sequential manner and produce a corresponding protein. Translation is known to consume most of the cell's energy. Maximizing the protein production rate in mRNA translation, subject to the bounded biomolecullar budget, is thus an important problem in both biology and biotechnology. We consider this problem using a mathematical model for mRNA translation called the ribosome flow model (RFM). For an mRNA strand with $n$ sites the RFM includes $n$ state-variables that encode the normalized ribosomal density at each site, and $n+1$ positive parameters: the initiation rate and elongation rates along the chain. An affine constraint on these rates is used to model the bounded cellular budget. We show that for a homogeneous constraint the rates that maximize the steady-state protein production rate have a special structure. They are symmetric with respect to the middle of the chain, and monotonically increase as we move towards the center of the chain. The ribosomal densities corresponding to the optimal rates monotonically decrease along the chain. We discuss some of the biological implications of these results.
An Augmented Framework for Practical Development of Construction Robots
Khaled Zied
International Journal of Advanced Robotic Systems , 2008,
Abstract: The use of robotic systems in performing construction tasks has great potential; however the development of such systems remains problematic. This is due to the lack of a suitable feasibility analysis that can help the decision makers to justify the use of robots and problems in the development process of the system itself. The multidisciplinary and complex nature of construction robotic systems requires a robust development framework for such systems. An augmented framework for the development of construction robots is explained in detail and practically applied to the Star lifter robotic system which is mainly designed to carry heavy tools for construction tasks. The framework consists of two models; the feasibility analysis model and the development process model. The feasibility analysis principles, methodology and tools are explained and discussed in detail. Systems Engineering model is used in the development of the system which allows complete analysis of the system hardware and software components. The purpose of the current project is to develop a general purpose robot that can be employed to perform different jobs to justify its use economically. The presented tools and processes can be utilised in the development of any similar systems.
A robust system for melanoma diagnosis using heterogeneous image databases  [PDF]
Khaled Taouil, Zied Chtourou, Nadra Ben Romdhane
Journal of Biomedical Science and Engineering (JBiSE) , 2010, DOI: 10.4236/jbise.2010.36080
Abstract: Early diagnosis of melanoma is essential for the fight against this skin cancer. Many melanoma detection systems have been developed in recent years. The growth of interest in telemedicine pushes for the development of offsite CADs. These tools might be used by general physicians and dermatologists as a second advice on submission of skin lesion slides via internet. They also can be used for indexation in medical content image base retrieval. A key issue inherent to these CADs is non-heterogeneity of databases obtained with different apparatuses and acquisition techniques and conditions. We hereafter address the problem of training database heterogeneity by developing a robust methodology for analysis and decision that deals with this problem by accurate choice of features according to the relevance of their discriminative attributes for neural network classification. The digitized lesion image is first of all segmented using a hybrid approach based on morphological treatments and active contours. Then, clinical descriptions of malignancy signs are quantified in a set of features that summarize the geometric and photometric features of the lesion. Sequential forward selection (SFS) method is applied to this set to select the most relevant features. A general regression network (GRNN) is then used for the classification of lesions. We tested this approach with color skin lesion images from digitized slides data base selected by expert dermatologists from the hospital “CHU de Rouen-France” and from the hospital “CHU Hédi Chaker de Sfax-Tunisia”. The performance of the system is assessed using the index area (Az) of the ROC curve (Receiver Operating Characteristic curve). The classification permitted to have an Az score of 89,10%.
Microstructure and Mechanical Properties of Nano-crystalline Al-8 wt pct Ni Alloy
MAbou Zied,

材料科学技术学报 , 2006,
Abstract: Microstructure and mechanical properties of ball-milled Al-8 wt pct Ni ribbon have been investigated by X-ray diffraction(XRD)and continuous Vickers hardness test, respectively. The results indicate that, the main phases of this alloy are α-Al and orthorhombic-Al3Ni. The lattice parameter of α-Al increases with increasing milling time. From the elastic constant of Al, the average contrast factors of the(111),(200),(220),(311)and system were calculated. The average grain size and dislocation parameters as a function of milling time have been investigated using the modified Williamson-Hall plot and the Warren-Averbach equation, respectively.An attempt has been made to correlate the micro-hardness of milled ribbon with their grain size through the Hall-Patch relationship:HV0.01=742.45〈D〉-1/2 401.55(kg/mm2).
A Protocol for Re-authentication and Handoff Notification in Wireless Mesh Networks
Ikbel Daly,Faouzi Zarai,Lotfi Kamoun
International Journal of Computer Science Issues , 2011,
Abstract: Mesh technology has captured the interest of university research and industry, because of its capacity to meet at the same time the requirements of Internet service provider and users. But, its architecture and configuration do not ensure a protection against the unauthorized use of the network since the used basic security measures do not include the concept of mobility. Our endeavor in this paper is to introduce a re-authentication scheme for secure handoff based on an efficient mobility management. First, we have treated the mobility aspect. Indeed, we applied the Mobility Notification Message procedure to support an environment which manages handoff in effective way. Then, using this technique, we have defined a new scheme to provide security during handoff. Our study shows that the proposed protocol can provide more protected network and more effective re-authentication scheme in term of minimized handoff latency as well as reduced blocking and loss rates.
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