Fatma Krichen

Extraction, characterization and antimicrobial activity of sulfated polysaccharides from fish skins

Sulfated polysaccharides were extracted from gray triggerfish (GTSP) and smooth hound (SHSP) skins. Their chemical and physical characteristics were determined using X-ray diffraction and Infrared spectroscopic analysis. The antibacterial activities of GTSP and SHSP against Listeria monocytogenes (ATCC 43251), Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), Salmonella enterica (ATCC 43972) and Enterobacter sp were evaluated by determining clear growth inhibition zone diameters and the minimum inhibitory concentration (MIC) values and by essays in liquid media. GTSP and SHSP were fractionated by a Diethylaminoethyl-cellulose chromatography. Fraction FGII, from GTSP, and fraction FSII, from SHSP, showed the most important inhibitory effects against the tested bacterial species. The sulfated polysaccharides from fish skins did not show hemolytic activity towards bovine erythrocytes. Overall, the results suggested that those polysaccharides could offer promising sources of polysaccharides for future application as dietary ingredients in the nutraceutical industry.

Structural characterization and functional properties of antihypertensive Cymodocea nodosa sulfated polysaccharide.

A sulfated polysaccharide was successfully isolated from Cymodocea nodosa (CNSP). This is the first report that indicates the chemical composition, structural characterization, functional and antihypertensive properties of this polysaccharide. The CNSP consisted mainly of sulfate (23.17%), total sugars (54.90%), galactose (44.89%), mannose (17.30%), arabinose (12.05%), xylose (9.18%), maltose (1.07%) and uronic acid (11.03%) with low water activity (0.49). CNSP had an XRD pattern that was typical for a semi-crystalline polymer with homogeneous structure. It also displayed an important anti-hypertensive activity (IC50=0.43mgml) with a dose-dependent manner using a synthetic substrate, N-hippuryl-His-Leu hydrate salt (HHL). Overall, the results indicate that CNSP have attractive chemical, functional and biological properties, with a preliminary structural may have a backbone of branched 6-O-sulfated (1→4) galactosidic linkages, which can be considered in the future as alternative additive in various foods, cosmetic and pharmaceutical preparations.

In vitro and in vivo anti-coagulant activity and toxicological studies of marine sulfated glycosaminoglycans.

The present study aimed to characterize and evaluate the in vitro and in vivo anticoagulant activity of sulfated glycosaminoglycans from the skins of smooth hound (SHSG) and grey triggerfish (GTSG). The analysis of SHSG and GTSG with acetate cellulose electrophoresis in Zn-acetate revealed the presence of hyaluronic acid (HA), chondroitin sulfate (CS) and dermatan sulfate (DS). Both glycosaminoglycans were evaluated for their in vitro anticoagulant activities using activated partial thromboplastin time (aPTT), thrombin time (TT) and prothrombine time (PT) tests. SHSG and GTSG and calciparin were tested as in vivo anticoagulants by subcutaneous (s.c) injection to adult female Wistar rats in a concentration of 75mg/kg of body weight. The administration of SHSG, GTSG and calciparin to rats induced a significant decrease of platelet rates compared to the control. The aPTT assay of SHSG and GTSG was prolonged 1.3 and 1.23-fold respectively compared with the control. Toxicity studies were performed to investigate whether or not SHSG and GTSG can cause pathological changes in the liver, proteins and DNA. The concentration and catalytic activity of liver oxidative stress markers and enzymes, respectively, as well as the observed hepatic morphological changes indicated that calciparin induced hepatic toxicity and oxidative damage in the liver. The higher activity and lower toxicity of SHSG and GTSG recommended these compounds as a better drug candidate than calciparin.

Purification, structural characterization and antiproliferative properties of chondroitin sulfate/dermatan sulfate from tunisian fish skins

Chondroitin sulfate/dermatan sulfate GAGs were extracted and purified from the skins of grey triggerfish (GTSG) and smooth hound (SHSG). The disaccharide composition produced by chondroitinase ABC treatment showed the presence of nonsulfated disaccharide, monosulfated disaccharides ΔDi6S and ΔDi4S, and disulfated disaccharides in different percentages. In particular, the nonsulfated disaccharide ΔDi0S of GTSG and SHSG were 3.5% and 5.5%, respectively, while monosulfated disaccharides ΔDi6S and ΔDi4S were evaluated to be 18.2%, 59% and 14.6%, 47.0%, respectively. Capillary elecrophoresis analysis of GTSG and SHSG contained 99.2% and 95.4% of chondroitin sulfate/dermatan sulfate, respectively. PAGE analysis showed a GTSG and SHSG having molecular masses with average values of 41.72KDa and 23.8KDa, respectively. HCT116 cell proliferation was inhibited (p<0.05) by 70.6% and 72.65% at 200μg/mL of GTSG and SHSG respectively. Both GTSG and SHSG demonstrated promising antiproliferative potential, which may be used as a novel, effective agent.

Potential application of Bacillus subtilis SPB1 lipopeptides in toothpaste formulation

Graphical abstract

C-SCRIP: Collaborative Security Pattern Integration Process

Collaboration is the act of working together, towards a common goal. Collaboration is essential to the success of construction project. In software engineering projects, understanding and supporting collaboration gives the broad impact on product quality. There appears that it is difficult to effectively interact and achieve a common project goals within the bounds of cost, quality and time. The purpose of the paper is to propose a collaborative engineering process, called Collaborative SeCurity patteRn Integration Process C-SCRIP, and a tool that supports the full life-cycle of the development of a secure system from modeling to code.

Anionic lipopeptides from Bacillus mojavensis I4 as effective antihypertensive agents: Production, characterization and identification

A new isolated Bacillus mojavensis strain I4 was found as producer of biosurfactants by different screening methods, such as parafilm M test, hemolytic activity, oil displacement test, emulsification index, surface tension, and lipase production assay. Enhanced biosurfactants production was obtained using glucose and glutamic acid as carbon and nitrogen sources, respectively. The optimal production of the biosurfactants was obtained by using a C/N ratio of 17, pH of 7.0, and temperature of 37°C. The surface tension was reduced to 29 mN/m and the emulsification index E24 of 62% was achieved after 72 h of culture. The purified biosurfactants showed stability with regard to surface tension reduction and emulsification in a wide range of temperatures (4–120°C), pH (4–10), and salinity (2–12% of NaCl). The thin‐layer chromatography showed that the produced biosurfactants were lipopeptides. The biosurfactants were characterized as a group of anionic lipopeptides with zeta potential measurement. Chromatographic characterization using HPLC revealed that I4 lipopeptides contained numerous isoforms and surfactin was the major component. Moreover, the I4 lipopeptides showed interesting angiotensin‐converting enzyme‐inhibitory activity.

A UML Based Deployment and Management Modeling for Cooperative and Distributed Applications

Thanks to the major evolutions in the communication technologies and in order to deal with a continuous increase in systems complexity, current applications have to cooperate to achieve a common goal. Modeling such cooperatives applications should stress regular context evolutions and increasingly users requirements. Therefore, we look for a model based solution suitable to cooperative application that can react in response to several unpredictable changes. Driven by the cooperative application structure, we propose, in this paper, an UML extension named “DM profile” ensuring a high-level description for modeling the deployment and its management in distributed application. The proposed contribution is validated through a “Follow Me” case study and implemented through an Eclipse plug-in.

Studies on European eel skin sulfated glycosaminoglycans: Recovery, structural characterization and anticoagulant activity

Abstract The goal of the present work was the extraction and structural characterization of novel sulfated glycosaminoglycans from European eel skin. The recovered glycosaminoglycans were physicochemically characterized and the uronic acid and sulfate contents were 35.12 ± 2.13% and 16.32 ± 0.4%, respectively. Cellulose acetate electrophoresis for extracted glycosaminoglycans was also investigated. Molecular weight of these sulfated glycosaminoglycans was determined (~37 kDa) by the gradient PAGE. Glycosaminoglycans obtained from the European eel were composed of non-sulfated, mono- and disulfated disaccharides. These sulfated glycosaminoglycans were evaluated for their in vitro anticoagulant activity using activated partial thromboplastin time, thrombin time and prothrombin time tests. The result showed that the recovered glycosaminoglycans exhibited interestingly anticoagulant activity. These glycosaminoglycans did not show haemolytic activity towards human erythrocytes. Furthermore, these bioactive substances can be explored as a functional food with antithrombotic function or used as source of anticoagulant drugs.

Monitoring of Service-Oriented Applications for the Reconstruction of Interactions Models

This work focuses on software applications designed using service-oriented architectural model. These applications consist of several Web Services from different sources working together, to obtain complex Web Services. Several events occur during the interaction between Web Services, such as degradation of QoS, breakdown of deployed services, etc. These events disrupt the communications. In our work we have developed a service-oriented application for a Smart City, we have deployed a monitoring mechanisms to examine a service oriented application architecture, monitor interactions and build the graphical representation of the architecture using graphs to view the interactions events.