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Auteur Mohamed Abdelhafid Hamidechi |
Documents disponibles écrits par cet auteur (3)
Affiner la recherche Interroger des sources externesApport des techniques moléculaires et bioinformatiques pour l'identification et la caractérisation fonctionnelle de germes causant les mammites subcliniques et les infections respiratoires chez les bovins à Constantine et à Batna. / Assia Guendouze
Titre : Apport des techniques moléculaires et bioinformatiques pour l'identification et la caractérisation fonctionnelle de germes causant les mammites subcliniques et les infections respiratoires chez les bovins à Constantine et à Batna. Type de document : texte imprimé Auteurs : Assia Guendouze, Auteur ; Mohamed Abdelhafid Hamidechi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 164 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Mammites subcliniques bovine MLADI-TOF MS quorum quenching lactonase Cattle Subclinical mastitis التهاب ضرع البقر تحت السريري MALDI-TOF MSإدراك الن صاب إنزيم اللاكتوناز Index. décimale : 570 Sciences de la vie. Biologie Résumé : The aim of this study is, firstly, to evaluate the method of MALDI-TOF MS for bacteriological identification in the case of subclinical mastitis in dairy cattle and secondly, to test a new antivirulent strategy against a bacterial species P. aeruginosa causing respiratory infections in calves.
The first part consists in identifying 14 bacteria responsible for subclinical mastitis by MALDI-TOF MS confronted with the 16S rDNA and the housekeeping gene rpoB sequencing technique. Our results showed high reliability of identification by MALDI-TOF MS at the species level covering 92.8% of cases (13 isolates) with a score greater than 2. MALDI-TOF MS and bioinformatic analysis are tools that can substitute the identification by simple sequencing using the 16S and rpoB rDNA genes.
The second part consists of evaluating the efficacy of the enzyme SsoPox-W263I, to prevent the establishment of virulence in three strains of Pseudomonas aeruginosa isolated from pneumonic calves, the model strain P. aeruginosa PAO1 and three human strains. For this, we evaluated in vitro the amount of pyocyanin, the proteolytic activity and the biofilm. In the presence of SsoPox W263I, we observed a decrease in proteolytic activity and the production of pyocyanin in 100% of the isolates. Biofilm synthesis decreased in 86% of isolates. The enzyme SsoPox W263I by
inhibition of quorum sensing attenuates the pathogenic power of P. aeruginosa. It can therefore be a promising alternative to conventional treatments.
Diplôme : Doctorat En ligne : ../theses/biologie/GUE7255.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10847 Apport des techniques moléculaires et bioinformatiques pour l'identification et la caractérisation fonctionnelle de germes causant les mammites subcliniques et les infections respiratoires chez les bovins à Constantine et à Batna. [texte imprimé] / Assia Guendouze, Auteur ; Mohamed Abdelhafid Hamidechi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 164 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Mammites subcliniques bovine MLADI-TOF MS quorum quenching lactonase Cattle Subclinical mastitis التهاب ضرع البقر تحت السريري MALDI-TOF MSإدراك الن صاب إنزيم اللاكتوناز Index. décimale : 570 Sciences de la vie. Biologie Résumé : The aim of this study is, firstly, to evaluate the method of MALDI-TOF MS for bacteriological identification in the case of subclinical mastitis in dairy cattle and secondly, to test a new antivirulent strategy against a bacterial species P. aeruginosa causing respiratory infections in calves.
The first part consists in identifying 14 bacteria responsible for subclinical mastitis by MALDI-TOF MS confronted with the 16S rDNA and the housekeeping gene rpoB sequencing technique. Our results showed high reliability of identification by MALDI-TOF MS at the species level covering 92.8% of cases (13 isolates) with a score greater than 2. MALDI-TOF MS and bioinformatic analysis are tools that can substitute the identification by simple sequencing using the 16S and rpoB rDNA genes.
The second part consists of evaluating the efficacy of the enzyme SsoPox-W263I, to prevent the establishment of virulence in three strains of Pseudomonas aeruginosa isolated from pneumonic calves, the model strain P. aeruginosa PAO1 and three human strains. For this, we evaluated in vitro the amount of pyocyanin, the proteolytic activity and the biofilm. In the presence of SsoPox W263I, we observed a decrease in proteolytic activity and the production of pyocyanin in 100% of the isolates. Biofilm synthesis decreased in 86% of isolates. The enzyme SsoPox W263I by
inhibition of quorum sensing attenuates the pathogenic power of P. aeruginosa. It can therefore be a promising alternative to conventional treatments.
Diplôme : Doctorat En ligne : ../theses/biologie/GUE7255.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10847 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité GUE/7255 GUE/7255 Thèse Bibliothèque principale Thèses Disponible
Titre : Approches génétique et bioinformatique pour la prédiction de la structure 3D de la PLP2a du gène mecA de Staphylococcus aureus. Type de document : texte imprimé Auteurs : Amina Ayeche, Auteur ; Mohamed Abdelhafid Hamidechi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 176 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Biochimie et Biologie Cellulaire et Moléculaire: Biochimie Appliquée SARM MALDI-TOF MS mecA PLP2a structure 3D MRSA PBP2a 3D structure البنیة ثلاثیة الأبعاد Index. décimale : 570 Sciences de la vie. Biologie Résumé :
Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health problem, causing both nosocomial and community-acquired infections worldwide. Methicillin resistance is generally due to the mecA gene which encodes an additional penicillin binding protein (PBP2a) with low affinity for methicillin and all beta-lactam antibiotics. The first part of our thesis, consists in identifying 65 isolates of S. aureus, collected from different pathological samples in Constantine, by MALDI-TOF MS. Our results showed a high reliability and rapid identification of S. aureus by proteomics technology MALDI-TOF MS compared to phenotypic and genotypic techniques (sequencing of the 16S rDNA). Resistance to methicillin in these strains was detected by the cefoxitin disk diffusion method in Mueller-Hinton agar, accompanied by the search for the mecA gene by RT-PCR. The comparison between these two methods revealed a high degree of correlation. The second part of our thesis, consists of the prediction of the secondary and tertiary structures of PBP2a in sillico by the use of appropriate bioinformatics tools. The knowledge of the 3D structure of PBP2a has allowed us to better understand its function as well as the resistance mechanism of MRSA to methicillin. Alignment of our tertiary structures of PLP2a of LISC8 and PMC1 isolates generated by MODELLER shows a mutation in positions 124 and 182 where asparagine ""N"" is substituted by lysine ""K"".Note de contenu :
Annexes.Diplôme : Doctorat En ligne : ../theses/biologie/AYE7529.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11368 Approches génétique et bioinformatique pour la prédiction de la structure 3D de la PLP2a du gène mecA de Staphylococcus aureus. [texte imprimé] / Amina Ayeche, Auteur ; Mohamed Abdelhafid Hamidechi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2019 . - 176 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Biochimie et Biologie Cellulaire et Moléculaire: Biochimie Appliquée SARM MALDI-TOF MS mecA PLP2a structure 3D MRSA PBP2a 3D structure البنیة ثلاثیة الأبعاد Index. décimale : 570 Sciences de la vie. Biologie Résumé :
Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health problem, causing both nosocomial and community-acquired infections worldwide. Methicillin resistance is generally due to the mecA gene which encodes an additional penicillin binding protein (PBP2a) with low affinity for methicillin and all beta-lactam antibiotics. The first part of our thesis, consists in identifying 65 isolates of S. aureus, collected from different pathological samples in Constantine, by MALDI-TOF MS. Our results showed a high reliability and rapid identification of S. aureus by proteomics technology MALDI-TOF MS compared to phenotypic and genotypic techniques (sequencing of the 16S rDNA). Resistance to methicillin in these strains was detected by the cefoxitin disk diffusion method in Mueller-Hinton agar, accompanied by the search for the mecA gene by RT-PCR. The comparison between these two methods revealed a high degree of correlation. The second part of our thesis, consists of the prediction of the secondary and tertiary structures of PBP2a in sillico by the use of appropriate bioinformatics tools. The knowledge of the 3D structure of PBP2a has allowed us to better understand its function as well as the resistance mechanism of MRSA to methicillin. Alignment of our tertiary structures of PLP2a of LISC8 and PMC1 isolates generated by MODELLER shows a mutation in positions 124 and 182 where asparagine ""N"" is substituted by lysine ""K"".Note de contenu :
Annexes.Diplôme : Doctorat En ligne : ../theses/biologie/AYE7529.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11368 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité AYE/7529 AYE/7529 Thèse Bibliothèque principale Thèses Disponible
Titre : Mise au point d’une méthode d’évaluation du risque bactérien par une approche a priori : Cas de la chaine de fabrication du lait pasteurisé. Type de document : texte imprimé Auteurs : Linda Boultifat, Auteur ; Mohamed Abdelhafid Hamidechi, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 107 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : SNV: Microbiologie MALDI-TOF MS ADNr 16S lait reconstitué pasteurisé Qualité hygiénique HACCP pathogènes 16S rDNA pasteurized reconstituted milk pathogens اللبن المبستر المعاد تشكيله مسببات الأمراض Index. décimale : 570 Sciences de la vie. Biologie Résumé : The objective of this study is, firstly, to emphasize the importance of adopting a microbiological risk assessment system and secondly, to evaluate the MALDI-TOF MS method as an effective and rapid tool for the identification of foodborne bacterial isolates. The microbiological analyzes results of the reconstituted pasteurized milk samples, collected at different stages of their manufacturing process, compared to the compliance limits indicated in the microbiological standards related to dairy products and derived products from the Algerian regulations in force, showed compliance at the level of the FAM, the search for other germs (Total and faecal Coliform , Clostridium sulfito-réducteur, Salmonella sp and Staphylococcus aureus) are revealed negative in these samples. However, contamination with coagulase-negative staphylococci species was detected. In this study, 12 bacteria species isolated from the same milk samples are identified by MALDI-TOF MS confronted with the 16S rDNA as a reference method. Our results shows high reliability of MALDI-TOF MS identification at the species level covering all isolates (100%) with a score >2. This study suggests that compared to the sequencing of the 16S rDNA gene that provides limited results; MALDI-TOF MS and bioinformatic analysis can be used for rapid and accurate identification of spoilage agents and pathogens in the dairy industry. These tools, once integrated with the implementation of preventive systems such as the HACCP, will significantly improve food security. Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/biologie/BOU7549.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11387 Mise au point d’une méthode d’évaluation du risque bactérien par une approche a priori : Cas de la chaine de fabrication du lait pasteurisé. [texte imprimé] / Linda Boultifat, Auteur ; Mohamed Abdelhafid Hamidechi, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2019 . - 107 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : SNV: Microbiologie MALDI-TOF MS ADNr 16S lait reconstitué pasteurisé Qualité hygiénique HACCP pathogènes 16S rDNA pasteurized reconstituted milk pathogens اللبن المبستر المعاد تشكيله مسببات الأمراض Index. décimale : 570 Sciences de la vie. Biologie Résumé : The objective of this study is, firstly, to emphasize the importance of adopting a microbiological risk assessment system and secondly, to evaluate the MALDI-TOF MS method as an effective and rapid tool for the identification of foodborne bacterial isolates. The microbiological analyzes results of the reconstituted pasteurized milk samples, collected at different stages of their manufacturing process, compared to the compliance limits indicated in the microbiological standards related to dairy products and derived products from the Algerian regulations in force, showed compliance at the level of the FAM, the search for other germs (Total and faecal Coliform , Clostridium sulfito-réducteur, Salmonella sp and Staphylococcus aureus) are revealed negative in these samples. However, contamination with coagulase-negative staphylococci species was detected. In this study, 12 bacteria species isolated from the same milk samples are identified by MALDI-TOF MS confronted with the 16S rDNA as a reference method. Our results shows high reliability of MALDI-TOF MS identification at the species level covering all isolates (100%) with a score >2. This study suggests that compared to the sequencing of the 16S rDNA gene that provides limited results; MALDI-TOF MS and bioinformatic analysis can be used for rapid and accurate identification of spoilage agents and pathogens in the dairy industry. These tools, once integrated with the implementation of preventive systems such as the HACCP, will significantly improve food security. Note de contenu :
Annexes.Diplôme : Doctorat en sciences En ligne : ../theses/biologie/BOU7549.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11387 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BOU/7549 BOU/7549 Thèse Bibliothèque principale Thèses Disponible
