In this study, Polyphenol oxidases (PPO) from royal dates fruit was purified and characterized .These procedures led to 8-fold purification with 14.72% recovery. Three isoenzymes of royal dates PPO exhibited a molecular weight of 20.,45... more
In this study, Polyphenol oxidases (PPO) from royal dates fruit was purified and characterized .These procedures led to 8-fold purification with 14.72% recovery. Three isoenzymes of royal dates PPO exhibited a molecular weight of 20.,45 and 64kDa.The royal date PPOs had maximum activity at pH 4.6 and 8, 3.6-5.6 and 5.6 with pyrogallol, 4-methylcatechol and pyrocatechol substrates, respectively. The enzyme showed high stability in the temperature range of 30-60°C.4-Methylcatechol was the most suitable substrate, due to the lowest Km and the biggest Vmax/Km values.The kinetic of thermal inactivation were performed in a temperature range of 60-75°C. A biphasic model provided a good description of dates PPO thermal inactivation.Indole-3acetic acid markedly inhibited Royal dates PPO activity. Its Anti-browning effect on dates was investigated .IAA-treatment reduced weight loss,pericarp decay,browning index and membrane electrolyte leakage.Thus,a higher total anthocyanins contents and total phenolic contents was correlated with higher DPPH scavenging activity and lower MDH contents Such effect was accredited to maintain of membrane integrity and inhibition of oxidative enzymes by IAA.In conclusion, IAA could be used as a potent inhibitor of fruits enzymatic browning reaction.
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707FN2 Bernard-Soulier syndrome (BSS) is an extremely rare inherited bleeding disorder characterized by a defect of the GPIb/IX/V complex, which is essential for hemostasis, as the GPIbα subunit binds to subendothelial von Willebrand... more
707FN2 Bernard-Soulier syndrome (BSS) is an extremely rare inherited bleeding disorder characterized by a defect of the GPIb/IX/V complex, which is essential for hemostasis, as the GPIbα subunit binds to subendothelial von Willebrand factor. Since the identification of the first mutation in 1990, almost one hundred cases carrying mutations in the GP1BA, GP1BB, and GP9 genes have been described. Most of the mutations prevent the coordinated association of the complex or binding to the von Willebrand factor. BSS is usually transmitted as a recessive trait with giant platelets and severe bleeding tendency. However, there are families with a dominant mild form, in which the affected individuals have only moderate macrothrombocytopenia and bleeding tendency. A correct definition of the clinical and laboratory features, together with accurate genotype/ phenotype correlation studies, remains essential for understanding the molecular basis of the disease and managing patients appropriately....
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Research Interests: Chemistry, Food Science, Yeast, Fermentation, Glycerol, and 2 moreCarotenoid and Rhodotorula(Carotenoid and Rhodotorula)
(Carotenoid and Rhodotorula)
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Abstract The immobilization of Fusarium solani β-glucosidase (FBgl1) on chitosan was performed to improve biocatalyst performance. Compared with free FBgl1, the immobilized biocatalyst exhibited a shift of the optimal temperature, a... more
Abstract The immobilization of Fusarium solani β-glucosidase (FBgl1) on chitosan was performed to improve biocatalyst performance. Compared with free FBgl1, the immobilized biocatalyst exhibited a shift of the optimal temperature, a conservation of the optimum pH with high residual activity at extreme acidic pH and an improved thermal stability. The immobilized enzyme was reusable up to 12 cycles. The FBgl1 immobilization enhanced its glucose and organic solvent tolerance. The free form of FBgl1 was unable to synthesize alkylglucosides, while the immobilized one was able to react using butanol as alcohol and either cellobiose or glucose as glucoside. The alkylglucosides were characterized by nuclear magnetic resonance as sec-butyl-β- d -glucoside and sec-butyl-β- d -cellobioside. It is worth noting that this last glucomolecule is synthesized for the first time using an enzymatic process. These butylglucosides exhibited a typical surfactant behavior (surface tension 26−35 mN/m and critical micellar concentration 250−1000 mg/L).
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Research Interests: Cancer, Biology, Cancer Research, Epigenetics, Medicine, and 15 moreMultivariate Analysis, Humans, Methylation, Female, Male, DNA methylation, Middle Aged, Adult, Base Sequence, Nasopharyngeal Carcinoma, Nasal Mucosa, Molecular Sequence Data, reverse transcriptase polymerase chain reaction, Neoplasm staging, and Nasopharynx
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This work is a comparative study of the effect of Alfa fibers treatments on the mechanical behavior of Alfa/Cereplast bio-composites. Various approaches have been used, including retting in salt water, hot water treatment, soda treatment... more
This work is a comparative study of the effect of Alfa fibers treatments on the mechanical behavior of Alfa/Cereplast bio-composites. Various approaches have been used, including retting in salt water, hot water treatment, soda treatment and enzymatic treatment (xylanase). The results of biochemical and morphological analyzes of the obtained fibers prove the increase of the cellulose content and the reduction of the size of the treated fibers. Alfa/Cereplast bio-composites were formulated with 20% of fibers using the twin-screw extrusion process followed by the injection molding. Tensile tests show the increase of the Young's moduli and the mechanical strengths as a function of cellulose content and fiber size. Enzymatic treatment records the best mechanical properties. 23 ème Congrès Français de Mécanique Lille, 28 Août au 1 er Septembre 2017 Mots clefs : Traitement enzymatique, Xylanase, Composition biochimique, propriétés morphologiques, propriétés mécaniques
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Poor interfacial adhesion between vegetable fibers and bio-based thermoplastics is recognized as a serious drawback for biocomposite materials. To be applicable for a large-scale production, one should consider appropriate methods of... more
Poor interfacial adhesion between vegetable fibers and bio-based thermoplastics is recognized as a serious drawback for biocomposite materials. To be applicable for a large-scale production, one should consider appropriate methods of natural fiber handling. This study presented poly(lactic acid) (PLA) reinforced with Alfa short fibers and four types of fiber treatment were selected. The effect of these treatments on the tensile properties and the morphology of biocomposites was studied. Composite samples were produced using a twin-screw extruder and an injection molding machine with a fiber percentage of 20 wt %. Prior to composite manufacture, Alfa fibers were subjected to mechanical, chemical and enzymatic modifications. The comparison of enzyme treated fibers and NaOH treated fibers was investigated by means of biochemical and morphological analyses. It was observed that enzymes decompose lignin, pectin and hemicelluloses from the fiber bundles interface leading to the reduction ...
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The lignocellulosic hydrolysate was used as the fermentation feedstock of Rhodotorula mucilaginosa Y-MG1 for the production of microbial lipids as the potential raw material for biodiesel synthesis. On synthetic media and under... more
The lignocellulosic hydrolysate was used as the fermentation feedstock of Rhodotorula mucilaginosa Y-MG1 for the production of microbial lipids as the potential raw material for biodiesel synthesis. On synthetic media and under nitrogen-limiting condition, the Y-MG1 strain produces 2.13 g/L of lipids corresponding to 32.7% of lipid content. This strain was able to assimilate a wide range of substrates, especially C5 and C6 sugars as well as glycerol and sucrose. Fatty acid composition shows a divergence depending on the nature of used carbon source with a predominance of oleic acid or linoleic acid. An effective hydrolysis process, based on diluted acid treatment, was established for providing the maximum of fermentable sugars from different characterized lignocellulosic wastes. The highest yield of reducing sugars (56.6 g/L) could be achieved when wheat bran was used as the raw material. Hydrolysate detoxification step was not required in this study since the Y-MG1 strain was shown...
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Latent membrane protein 1 (LMP1) encoded by the Epstein-Barr virus (EBV) plays an important role in EBV-induced cell transformation. Down-regulation of the LMP1 expression had shown promising results on cancer cell therapy. In this study,... more
Latent membrane protein 1 (LMP1) encoded by the Epstein-Barr virus (EBV) plays an important role in EBV-induced cell transformation. Down-regulation of the LMP1 expression had shown promising results on cancer cell therapy. In this study, we identified by Phage display a novel peptide called B1.12 (ACPLDLRSPCG) which selectively binds to the extracellular loop (B1) of the LMP1 oncoprotein as demonstrated by molecular docking, NMR and ITC. Using an LMP1 expressing cell line, we showed that B1.12 decreased cell viability, and induced G0/G1 cell cycle arrest. In addition, the expression of A20, pAkt, and pNFkb (pRelA536) in C666-1 cells treated with B1.12 decreased compared to the untreated cells. In conclusion, we selected a novel peptide able to bind specifically to the extracellular loop of LMP1 and thus modulate its oncogenic properties.
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Nasopharyngeal carcinoma (NPC) is an unusual head and neck cancer because of its unequal geographical distribution and its consistent association with the Epstein-Barr virus (EBV). This malignant tumor poses a serious public health... more
Nasopharyngeal carcinoma (NPC) is an unusual head and neck cancer because of its unequal geographical distribution and its consistent association with the Epstein-Barr virus (EBV). This malignant tumor poses a serious public health problem in many countries, especially in Southeast Asia and North Africa where the recorded incidence are highest. During the past decade, a growing number of studies were undertaken to define the molecular basis of NPC. However, the analysis of several clinical and biological parameters of North African and Southeast Asian NPCs has shown notable differences, suggesting that they could result from a distinct combination of etiological factors. One intriguing characteristic of North African NPC, concerns its bimodal age distribution with a secondary peak of incidence in the range of 15-25 years, not observed in Asian NPC. In this juvenile form of NPC, immuno-histochemistry assay has shown that the two key proteins controlling the apoptotic-survival balance...
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In previous work, a new class of synthesized bioactive compounds of Morita-Baylis-Hillman adducts (MBH) showed an antioxidant and anti melanogensis activity [17–23]. Accordingly, in the present work the relationship between antifungal... more
In previous work, a new class of synthesized bioactive compounds of Morita-Baylis-Hillman adducts (MBH) showed an antioxidant and anti melanogensis activity [17–23]. Accordingly, in the present work the relationship between antifungal activity and the responsible chemical function of MBH adducts and their derivatives (alcohols, acetates, phosphonates and hydrazono phosphonates) was investigated against plant pathogenic fungi Aspergillus niger, Fusarium oxysporum, Penicillium occitanis, Trichoderma reesei, Stachybotrys microspora, Fusarium solani, Trichoderma parceramosum, fusarium aethiopicum, Alternaria alternata and Aspergillus flavus using the agar diffusion method. Results showed acetates displayed varying degrees of antifungal activity against several fungi tested, while just one alcohol compound showed lower activity. The derivative with five carbon (2g) was the most powerful with an inhibitor growth zone diameter of 4.75 ÷ 0.21, 6.1 ± 0.14, 4.35 ± 0.21, 3.9 ± 0.14, 4.54 ± 0.1...
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BACKGROUND Serine proteases have long been recognized to play key roles in various physiological processes. However, their disequilibrium can be linked to several diseases. Taking into account their wide diversity and specificity, they... more
BACKGROUND Serine proteases have long been recognized to play key roles in various physiological processes. However, their disequilibrium can be linked to several diseases. Taking into account their wide diversity and specificity, they have been actively investigated by many industrial, academic and pharmaceutical industries. OBJECTIVE This review aims to provide a concise analysis of the described serine proteases as well as their relevant biotechnological and therapeutic applications. METHOD Here, we give an overview of the recent knowledge on serine proteases with a particular focus on their biotechnological applications reported in European Patent Office (Espacenet), United States Patent and National Patent Collections (WIPO) patent databases. RESULTS Serine proteases are probably the enzymes that have been mostly studied over the past few decades. However, despite their increasing interest, no significant patent so far has dealt with the identity of overactive serine proteases in disease settings. CONCLUSION This review displays that serine proteases have several relevant industrial uses. New potential applications of such proteins require more functional analyses seeing the key role of serine proteases in many biomedical and biotechnological processes.
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Research Interests: Chemistry, Biodiesel, Biofuel, Yeast, Raw Material, and 3 moreBiodiesel Production, Glycerol, and Crude Oil
Pectin lyase (pnl) is the only pectinase able to hydrolyze directly the highly methylated pectin without liberating the toxic methanol and without disturbing ester content responsible for specific aroma of juices. The cDNA of Penicillium... more
Pectin lyase (pnl) is the only pectinase able to hydrolyze directly the highly methylated pectin without liberating the toxic methanol and without disturbing ester content responsible for specific aroma of juices. The cDNA of Penicillium occitanis pnl (mature form) was cloned into pET-21a as expression vector and over-expressed into Esherichia coli. Most of recombinant pnl was expressed as inclusion bodies. Pnl activity was confirmed by colorimetric assay. To enhance the solubility yield of the expressed pnl, the effects of induction temperature, host strain and expression level were optimized. Maximal production of functional pnl was obtained after induction by 0.4mM IPTG at 30°C and 150rpm for 16h. Interestingly, the use of Origami host strain, having an oxidized cytoplasm favoring disulfide bonds formation required for the active conformation of the enzyme, has significantly improved the yield of the soluble active form of recombinant pnl. This pnl was successfully purified throu...
Research Interests: Biochemistry, Chemistry, Chromatography, Medicine, Gene expression, and 12 moreEscherichia coli, Temperature, Affinity chromatography, Solubility, Inclusion Bodies, Pectinase, Molecular cloning, Penicillium, Recombinant Proteins, Biological Macromolecules, Biochemistry and cell biology, and Protein refolding
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This work mainly focused on the production of an efficient, economical, and eco-friendly lipase (AKL29) from Actinomadura keratinilytica strain Cpt29 isolated from poultry compost in north east of Algeria, for use in detergent industries.... more
This work mainly focused on the production of an efficient, economical, and eco-friendly lipase (AKL29) from Actinomadura keratinilytica strain Cpt29 isolated from poultry compost in north east of Algeria, for use in detergent industries. AKL29 shows a significant lipase activity (45 U/mL) towards hydrolyzed triacylglycerols, indicating that it is a true lipase. For maximum lipase production the modeling and optimization of potential culture parameters such as incubation temperature, cultivation time, and Tween 80 (v/v) were built using RSM and ANN approaches. The results show that both the two models provided good quality predictions, yet the ANN showed a clear superiority over RSM for both data fitting and estimation capabilities. A 4.1-fold increase in lipase production was recorded under the following optimal condition: incubation temperature (37.9 °C), cultivation time (111 h), and Tween 80 (3.27%, v/v). Furthermore, the partially purified lipase showed good stability, high com...
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The transcription factor tumor protein p53 (P53) controls a variety of genes most involved in cell cycle and is at the origin of apoptosis when DNA is irreparably damaged. We planned to select novel tumor protein p53-interacting peptides... more
The transcription factor tumor protein p53 (P53) controls a variety of genes most involved in cell cycle and is at the origin of apoptosis when DNA is irreparably damaged. We planned to select novel tumor protein p53-interacting peptides through the screening of hepta-peptide phage-display libraries. For this aim, human tumor suppressor protein p53 was expressed in Escherichia coli as Glutathione S-transferase fusion and purified by affinity chromatography. The phage library was then screened on this immobilized protein target. After three rounds of panning, phages were sequenced and shown to contain a consensus sequence NPNSAQG. Thereafter, either free p53 liberated from the fusion protein through thrombin treatment or Histidine-tagged p53 were recognized efficiently by the selected phage. To locate the p53-binding epitope of the selected hepta-peptide, three long peptides parts of the three known domains of the protein were synthesized and screened by the selected phage/peptide. T...
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Increased protease activity has been linked to the pathogenesis of IBD. While most studies have been focusing on host proteases in gut inflammation, it remains unclear how to address the potential contribution of their bacterial... more
Increased protease activity has been linked to the pathogenesis of IBD. While most studies have been focusing on host proteases in gut inflammation, it remains unclear how to address the potential contribution of their bacterial counterparts. In the present study, we report a functional characterization of a newly identified serine protease, SP-1, from the human gut microbiota. The serine protease repertoire of gut Clostridium was first explored, and the specificity of SP-1 was analyzed using a combinatorial chemistry method. Combining in vitro analyses and a mouse model of colitis, we show that oral administration of recombinant bacteria secreting SP-1 (i) compromises the epithelial barrier, (ii) alters the microbial community, and (ii) exacerbates colitis. These findings suggest that gut microbial protease activity may constitute a valuable contributor to IBD and could, therefore, represent a promising target for the treatment of the disease.
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Sepia officinalis produces a dark ink constituted of a suspension of melanin granules in a viscous colourless medium showing a large variability in composition. The examination of the spectra obtained by scanning electron microscopy of... more
Sepia officinalis produces a dark ink constituted of a suspension of melanin granules in a viscous colourless medium showing a large variability in composition. The examination of the spectra obtained by scanning electron microscopy of crude and the melanin-free ink showed slight variation in elemental composition related to the elimination of melanin substance after centrifugation. Ink elemental content varied also depending on the period of sampling. Temperature, light and oxygen can be considered as coagulation factors. Temperature around ambient temperature (e.g. 30°C) gave strong coagulation, while lower temperature (2–4°C), lack of oxygen and darkness greatly inhibited the ink coagulation process. Moreover, we showed that hydrogen peroxide activated the ink coagulation process and the coagulation rate depends on the amount of H2O2 added. Heat treatment (100°C for 5 minutes) of ink inhibited the coagulation. Interestingly, the addition of an adequate volume of fresh melanin-fre...