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Partager le résultat de cette recherche Interroger des sources externesEffet de l’herbicide sulfonylurée tribenuron méthyle sur la croissance de souches telluriques d’actinobactéries. / Kounouz Rachedi
Titre : Effet de l’herbicide sulfonylurée tribenuron méthyle sur la croissance de souches telluriques d’actinobactéries. : Caractérisation des isolats résistants et tests de dégradabilité Type de document : texte imprimé Auteurs : Kounouz Rachedi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2017 Importance : 100 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Streptomyces Tribenuron méthyle Résistance Hydrolyse acide Cométabolisme ARNr 16S Tribenuron methyl Resistance Acido-hydrolysis Co-metabolism 16S rRNA genes tribenuron Streptomycesالميثيل مقاومة تحليل حمضي الأيض المشترك .S16 ARNr جينات Index. décimale : 570 Sciences de la vie. Biologie Résumé : Granstar® 75 DF is one of the most used sulfonylurea herbicide on cereal crops; it contains 75
% of tribenuron-methyl (TBM). Assessing the changes on soil microbiota, particularly on the
most abundant bacterial groups, will be a useful approach to determine the impact of
Granstar® herbicide. For this purpose, Actinobacteria were analysed. They are known for their
abundance and aptitude to resist to xenobiotic substances. Using a selective medium for
Actinobacteria, forty two (42) strains were isolated from both untreated and Granstar® treated
soils. The number of isolates recovered from the treated agricultural soil 2 was fewer than that
isolated from the corresponding untreated soil, suggesting a negative effect of Granstar®
herbicide on Actinobacteria community. Among the isolates, eleven (11) resistant strains,
tolerating high doses of Granstar® ranging from 0.3 to 0.6% (v/v), were selected.
Morphological characterization of strains indicated their affiliation to Streptomyces genus.
The phylogenetic analysis, based on 16S rRNA genes sequencing, clustered five strains
(SRK3, SRK4, SRK9, SRK11 and SRK18) to Streptomyces rubrocyanodiastaticus sp. piger
type strain, with high bootstrap rates varying from 69 to 98%. While SRK13 and SRK14 were
closely related to Streptomyces lavendulocolor and SRK17 to Streptomyces africanus, with
high bootstrap values of 92; 89 and 76% respectively. SRK12 and SRK16 strains were
associated to four Streptomyces type strains (S. vinaceusdrappus, S. mutabilis, S. ghanaensis
and S. enissocaesilis) with a percentage of 70% of bootstrap. Strain SRK15 was related to
Streptomyces diastaticus sp. ardesiacus with high bootstrap level of 92%. The two most
resistant strains SRK12 and SRK17 did not grow on TBM as the sole carbon source, so they
were incapable of degrading it under these conditions. However, in the presence of glucose,
both tolerated its presence, but their growth was affected, compared to that on glucose, used
alone. At the final pH of 6.78-6.79, the TBM was already predominantly and chemically
degraded to an average rate of 76.18%. By decreasing the pH to 6.72-6.73, the TBM
dissipation increased significantly to an average of 89.36%. Furthermore, at lower acid values
of 4.38 and 4.23; obtained with a similar medium composition supplemented with glucose,
the disappearance of the TBM was further improved by 2.26 and 5.56% respectively with the
strains SRK12 and SRK17. Therefore, as the pH decreased, the TBM was more degraded
probably by acid hydrolysis. In all the tests carried out, as the TBM disappeared, two
compounds appeared in the medium and seemed to do not be affected by the acidity. On the
basis of these observations, it was suggested that the acid hydrolysis of the herbicide may be
the result of a co-metabolic process, due to the bacterial activity on another easily
metabolizable substrate. Such a process would be interesting to consider in the bioremediation
of alkaline soils polluted by TBM. The products of the TBM transformation were not
degraded chemically nor by the studied strains and had a negative effect on the growth of
these strains. This observation leaded to the need of more investigations on these compounds,
in particular their identification and the determination of their fate in the soil.
Diplôme : Doctorat en sciences En ligne : ../theses/biologie/RAC7160.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10437 Effet de l’herbicide sulfonylurée tribenuron méthyle sur la croissance de souches telluriques d’actinobactéries. : Caractérisation des isolats résistants et tests de dégradabilité [texte imprimé] / Kounouz Rachedi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2017 . - 100 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Streptomyces Tribenuron méthyle Résistance Hydrolyse acide Cométabolisme ARNr 16S Tribenuron methyl Resistance Acido-hydrolysis Co-metabolism 16S rRNA genes tribenuron Streptomycesالميثيل مقاومة تحليل حمضي الأيض المشترك .S16 ARNr جينات Index. décimale : 570 Sciences de la vie. Biologie Résumé : Granstar® 75 DF is one of the most used sulfonylurea herbicide on cereal crops; it contains 75
% of tribenuron-methyl (TBM). Assessing the changes on soil microbiota, particularly on the
most abundant bacterial groups, will be a useful approach to determine the impact of
Granstar® herbicide. For this purpose, Actinobacteria were analysed. They are known for their
abundance and aptitude to resist to xenobiotic substances. Using a selective medium for
Actinobacteria, forty two (42) strains were isolated from both untreated and Granstar® treated
soils. The number of isolates recovered from the treated agricultural soil 2 was fewer than that
isolated from the corresponding untreated soil, suggesting a negative effect of Granstar®
herbicide on Actinobacteria community. Among the isolates, eleven (11) resistant strains,
tolerating high doses of Granstar® ranging from 0.3 to 0.6% (v/v), were selected.
Morphological characterization of strains indicated their affiliation to Streptomyces genus.
The phylogenetic analysis, based on 16S rRNA genes sequencing, clustered five strains
(SRK3, SRK4, SRK9, SRK11 and SRK18) to Streptomyces rubrocyanodiastaticus sp. piger
type strain, with high bootstrap rates varying from 69 to 98%. While SRK13 and SRK14 were
closely related to Streptomyces lavendulocolor and SRK17 to Streptomyces africanus, with
high bootstrap values of 92; 89 and 76% respectively. SRK12 and SRK16 strains were
associated to four Streptomyces type strains (S. vinaceusdrappus, S. mutabilis, S. ghanaensis
and S. enissocaesilis) with a percentage of 70% of bootstrap. Strain SRK15 was related to
Streptomyces diastaticus sp. ardesiacus with high bootstrap level of 92%. The two most
resistant strains SRK12 and SRK17 did not grow on TBM as the sole carbon source, so they
were incapable of degrading it under these conditions. However, in the presence of glucose,
both tolerated its presence, but their growth was affected, compared to that on glucose, used
alone. At the final pH of 6.78-6.79, the TBM was already predominantly and chemically
degraded to an average rate of 76.18%. By decreasing the pH to 6.72-6.73, the TBM
dissipation increased significantly to an average of 89.36%. Furthermore, at lower acid values
of 4.38 and 4.23; obtained with a similar medium composition supplemented with glucose,
the disappearance of the TBM was further improved by 2.26 and 5.56% respectively with the
strains SRK12 and SRK17. Therefore, as the pH decreased, the TBM was more degraded
probably by acid hydrolysis. In all the tests carried out, as the TBM disappeared, two
compounds appeared in the medium and seemed to do not be affected by the acidity. On the
basis of these observations, it was suggested that the acid hydrolysis of the herbicide may be
the result of a co-metabolic process, due to the bacterial activity on another easily
metabolizable substrate. Such a process would be interesting to consider in the bioremediation
of alkaline soils polluted by TBM. The products of the TBM transformation were not
degraded chemically nor by the studied strains and had a negative effect on the growth of
these strains. This observation leaded to the need of more investigations on these compounds,
in particular their identification and the determination of their fate in the soil.
Diplôme : Doctorat en sciences En ligne : ../theses/biologie/RAC7160.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10437 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité RAC/7160 RAC/7160 Thèse Bibliothèque principale Thèses Disponible
Titre : Etude de l’aptitude des souches fongiques, isolées de la rhizosphère de deux plantes steppiques de la région minière d’Ain-Babouche, à la remédiation des sols métallifères. Type de document : texte imprimé Auteurs : Ouissem Meghnous, Auteur ; L. Dehimat, Directeur de thèse ; Oualida Rached-Mosbah, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 175 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponiblesLangues : Français (fre) Catégories : Français - Anglais
BiologieTags : Microbiologie :Biotechnologie et Bioprocédés, Applications Mycologiques Mycoendophytes Hedysarum pallidum Desf. Lygeum spartum. L antimoine arsenic résistance bioaccumulation stress oxydatif bioremédiation antimony resistance oxidative stress bioremedation الفطریات الداخلیة الإثمد الزرنیخ المقاومة الامتصاص الحیوي الإجھاد الأكسدي الإصلاح الحیوي Index. décimale : 570 Sciences de la vie. Biologie Résumé : The aim of this work is to highlight a resistant endophytic mycoflora in the roots of two metallophylic species Hedysarum pallidum Desf. and Lygeum spartum L. growing on soil contaminated with antimony (Sb) and arsenic (As) in Djebel Hamimat (Algeria) region, to study the toxicity of mycoendophytes with respect to toxicity of Sb and As, to evaluate the level of oxidative stress and the antioxidant defense systems of Aspergillus tubingensis and Fusarium oxyporum induced by metalloid toxicity. Our work demonstrates, the presence of mycoendophytes associated with the roots of the two plant species studied for the first time in Algeria; H. pallidum, and L. spartum. This latter have a colonization frequencies of 64.58% and 96.87% respectively. among the isolated mycoendophytes, only Aspergillus tubingensis was resistant to 500 mM Sb, and Fusarium oxysporum tolerated 30 mM As. The toxicity tests in vitro on A. tubingensis and F. oxysporum revealed that these strains accumulated a significant amounts of Sb in their biomass, in contrast to As. As regards the indicators of the oxidative stress level and the antioxidant responses of the two endophytic species, MDA, H2O2 and intracellular proline content increase significantly with increasing doses of Sb and As in the culture medium. Antioxidant responses vary quantitatively and qualitatively from a fungal species to another, and from a metalloid to another. This suggests that these endophytic strains may be potential agents for the bioremediation of soil and aquatic environments contaminated with antimony and arsenic.
Note de contenu : Annexe 1 : Les milieux de cultures
Annexe 2 : Extraction d’ADN génomique des mycoendophytes Résistants
Annexe 3 : Courbes étalons
Annexe 4 : Matrices de corrélation
article: Oxidative and antioxidative responses to antimony stress by endophytic fungus Aspergillus tubingensis isolated from antimony accumulator Hedysarum pallidum Desf.
Ouissem Meghnous1 & Laid Dehimat2 & Patrick Doumas3 & Mounia Kassa-Laouar1 & Fawzia Mosbah1 &
Oualida RachedDiplôme : Doctorat En ligne : ../theses/biologie/MEG7633.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11334 Etude de l’aptitude des souches fongiques, isolées de la rhizosphère de deux plantes steppiques de la région minière d’Ain-Babouche, à la remédiation des sols métallifères. [texte imprimé] / Ouissem Meghnous, Auteur ; L. Dehimat, Directeur de thèse ; Oualida Rached-Mosbah, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2020 . - 175 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Microbiologie :Biotechnologie et Bioprocédés, Applications Mycologiques Mycoendophytes Hedysarum pallidum Desf. Lygeum spartum. L antimoine arsenic résistance bioaccumulation stress oxydatif bioremédiation antimony resistance oxidative stress bioremedation الفطریات الداخلیة الإثمد الزرنیخ المقاومة الامتصاص الحیوي الإجھاد الأكسدي الإصلاح الحیوي Index. décimale : 570 Sciences de la vie. Biologie Résumé : The aim of this work is to highlight a resistant endophytic mycoflora in the roots of two metallophylic species Hedysarum pallidum Desf. and Lygeum spartum L. growing on soil contaminated with antimony (Sb) and arsenic (As) in Djebel Hamimat (Algeria) region, to study the toxicity of mycoendophytes with respect to toxicity of Sb and As, to evaluate the level of oxidative stress and the antioxidant defense systems of Aspergillus tubingensis and Fusarium oxyporum induced by metalloid toxicity. Our work demonstrates, the presence of mycoendophytes associated with the roots of the two plant species studied for the first time in Algeria; H. pallidum, and L. spartum. This latter have a colonization frequencies of 64.58% and 96.87% respectively. among the isolated mycoendophytes, only Aspergillus tubingensis was resistant to 500 mM Sb, and Fusarium oxysporum tolerated 30 mM As. The toxicity tests in vitro on A. tubingensis and F. oxysporum revealed that these strains accumulated a significant amounts of Sb in their biomass, in contrast to As. As regards the indicators of the oxidative stress level and the antioxidant responses of the two endophytic species, MDA, H2O2 and intracellular proline content increase significantly with increasing doses of Sb and As in the culture medium. Antioxidant responses vary quantitatively and qualitatively from a fungal species to another, and from a metalloid to another. This suggests that these endophytic strains may be potential agents for the bioremediation of soil and aquatic environments contaminated with antimony and arsenic.
Note de contenu : Annexe 1 : Les milieux de cultures
Annexe 2 : Extraction d’ADN génomique des mycoendophytes Résistants
Annexe 3 : Courbes étalons
Annexe 4 : Matrices de corrélation
article: Oxidative and antioxidative responses to antimony stress by endophytic fungus Aspergillus tubingensis isolated from antimony accumulator Hedysarum pallidum Desf.
Ouissem Meghnous1 & Laid Dehimat2 & Patrick Doumas3 & Mounia Kassa-Laouar1 & Fawzia Mosbah1 &
Oualida RachedDiplôme : Doctorat En ligne : ../theses/biologie/MEG7633.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11334 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité MEG/7633 MEG/7633 Thèse Bibliothèque principale Thèses Disponible
Titre : Caractérisation moléculaire et par MALDI-TOF MS des espèces fongiques phytopathogènes inféodées aux céréales et mise en évidence de l’impact de l’utilisation des antifongiques azolés sur la résistance des souches. Type de document : texte imprimé Auteurs : Ahlem Zaamouchi, Auteur ; Ilhem Mihoubi-Djezzare, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2019 Importance : 139 f. Format : 30 cm. Note générale : Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Microbiologie: Bioprocédés et Biotechnologie, Applications Mycologiques Blé dur Fongicides triazolés MALDI-TOF MS Résistance CYP 51A Durum wheat Triazole fungicides Resistance cyp51A الجين cyp51Aالقمح الصلب مبيدات فطرية التريازولات المقاومة مصفوفة المساعدة بالليزر و الامتزاز التايني في وقت الرحلة الكتلية الطيفية Index. décimale : 570 Sciences de la vie. Biologie Résumé :
Winter cereals including wheat remain the staple food of the Algerian diet and show a strategic importance in both human and animal nutrition. Many fungal diseases may attack wheat farmings, These attacks may cause great loss when the used varieties are sensitive. The mildews are phytopathogenic But, they are eventually responsible of human pathologies. The treatment protects the plant from every external contamination. The best phytosanitary protection of wheat farmingsis assured via two types of treatments; fungicidal and insecticide. The fungicides if used to destroy pathogenic fungi which attach the farmings, seeds and harvested products. Currently, the mildews are becoming resistant in the environment, because of the exercised pressure through the use of fungicides. The most common mildew’s resistance mechanism is the mutation of the cyp51 gene coding 14alpha-Demethylase sterol. The azolated antifungals inhibit this enzyme, leading to blocking the biosynthesis of the ergosterol which leads to deplete the ergosterol And to an accumulation of toxic metabolites. In this context, we have conducted a comparative study both seed samples, leaves and wheat spikes: one of them is treated by the azolated fungicide of type: Raxil® 060 FS, l’Artea330EC and Amistar® Xtra while the other is kept untreated in order to evaluate the
efficiency of triazoles and the degree of protection of the wheat farming after a fungicidal treatment in the province of Constantine (Algeria). According to the mycological analysis of the samples, 114 strains have been isolated; the species of Aspergillus and Penicillium genus are the most dominant. 6 species resistant against the treatments were selected for the study of fungicidal effects including (A. flavus, A. tubingensis, P. glabrum, P.griseofulvum, T. harzianium and A. alternate). The study of the sensitivity of these isolates covers firstly the evaluation of the in vitro activity of the pre-described fungicides via a diffusion technique. In addition, the obtained results validated with a statistical analysis revealed that the tested fungicides caused a decrease in the pycnidial Coating compared to control samples. Secondly, the detection of resistance mutations in the isolate’s cyp51 gene was accomplished through the analysis of this latter. The obtained results were treated using a bioinformatics approach in order to exploit them.
Note de contenu :
Annexes.
Diplôme : Doctorat En ligne : ../theses/biologie/ZAA7453.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11238 Caractérisation moléculaire et par MALDI-TOF MS des espèces fongiques phytopathogènes inféodées aux céréales et mise en évidence de l’impact de l’utilisation des antifongiques azolés sur la résistance des souches. [texte imprimé] / Ahlem Zaamouchi, Auteur ; Ilhem Mihoubi-Djezzare, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2019 . - 139 f. ; 30 cm.
Doctorat 3éme CYCLE LMD.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Microbiologie: Bioprocédés et Biotechnologie, Applications Mycologiques Blé dur Fongicides triazolés MALDI-TOF MS Résistance CYP 51A Durum wheat Triazole fungicides Resistance cyp51A الجين cyp51Aالقمح الصلب مبيدات فطرية التريازولات المقاومة مصفوفة المساعدة بالليزر و الامتزاز التايني في وقت الرحلة الكتلية الطيفية Index. décimale : 570 Sciences de la vie. Biologie Résumé :
Winter cereals including wheat remain the staple food of the Algerian diet and show a strategic importance in both human and animal nutrition. Many fungal diseases may attack wheat farmings, These attacks may cause great loss when the used varieties are sensitive. The mildews are phytopathogenic But, they are eventually responsible of human pathologies. The treatment protects the plant from every external contamination. The best phytosanitary protection of wheat farmingsis assured via two types of treatments; fungicidal and insecticide. The fungicides if used to destroy pathogenic fungi which attach the farmings, seeds and harvested products. Currently, the mildews are becoming resistant in the environment, because of the exercised pressure through the use of fungicides. The most common mildew’s resistance mechanism is the mutation of the cyp51 gene coding 14alpha-Demethylase sterol. The azolated antifungals inhibit this enzyme, leading to blocking the biosynthesis of the ergosterol which leads to deplete the ergosterol And to an accumulation of toxic metabolites. In this context, we have conducted a comparative study both seed samples, leaves and wheat spikes: one of them is treated by the azolated fungicide of type: Raxil® 060 FS, l’Artea330EC and Amistar® Xtra while the other is kept untreated in order to evaluate the
efficiency of triazoles and the degree of protection of the wheat farming after a fungicidal treatment in the province of Constantine (Algeria). According to the mycological analysis of the samples, 114 strains have been isolated; the species of Aspergillus and Penicillium genus are the most dominant. 6 species resistant against the treatments were selected for the study of fungicidal effects including (A. flavus, A. tubingensis, P. glabrum, P.griseofulvum, T. harzianium and A. alternate). The study of the sensitivity of these isolates covers firstly the evaluation of the in vitro activity of the pre-described fungicides via a diffusion technique. In addition, the obtained results validated with a statistical analysis revealed that the tested fungicides caused a decrease in the pycnidial Coating compared to control samples. Secondly, the detection of resistance mutations in the isolate’s cyp51 gene was accomplished through the analysis of this latter. The obtained results were treated using a bioinformatics approach in order to exploit them.
Note de contenu :
Annexes.
Diplôme : Doctorat En ligne : ../theses/biologie/ZAA7453.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11238 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité ZAA/7453 ZAA/7453 Thèse Bibliothèque principale Thèses Disponible
Titre : Étude des mécanismes de résistance de bactéries endophytes isolées à partir des racines d’Hedysarum pallidum et de Lygeum spartum poussant sur des déblais de mine d’antimoine. Type de document : texte imprimé Auteurs : Mounia Kassa Laouar ép Chouikh, Auteur ; Aicha Mechakra (Née Maza), Directeur de thèse ; Oualida Rached-Mosbah, Directeur de thèse Mention d'édition : 09/07/2020 Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2020 Importance : 183 f. Format : 30 cm. Note générale : 1 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Biochimie et Biologie Cellulaire et Moléculaire: Biochimie-Microbiologie appliquée bactéries endophytes métalloïdes stress oxydatif H2O2 MDA proline enzymes
antioxydantes biofilm transformation résistance bacterial endophytes metalloids oxidative stress antioxidant enzymes resistance البكتيريا الداخلية المعادن الثقيلة الإجهاد التأكسدي H2O2البرولين إنزيمات مضادات الأكسدة المقاومة التحولIndex. décimale : 570 Sciences de la vie. Biologie Résumé :
This work focuses on the study of the endophytic bacterial flora of H. pallidum and L. spartum roots, growing on the soil of mining region polluted by Sb and As, and the determination of the physiological, biochemical and molecular defense mechanisms adopted by this microflora to fight against metallic stress. The morphological and biochemical analyzes reveal a high biodiversity of this endophytic microflora. The study of the Sb and As toxicity allows the selection of two strains having the highest MICs, namely 450 mM of Sb and 175 mM of As. The molecular identification of resistant strains via 16S RNA gene sequencing shows that they are identical and belong to the Serratia marcescens species with 99% homology. The batch culture in presence of gradual Sb and As concentrations reveals a progressive decrease in bacterial growth of the two strains. Moreover, the measurement of oxidative stress parameters indicates a significant increase in the H2O2 amount, the MDA amount, the intracellular proline and even the activities of antioxidant enzymes, except at high thresholds in Sb and As. These enzymes permit the detoxification of the bacteria by elimination of the H2O2 and the other free radicals generated by metallic stress. In addition, the study of the resistance of S. marcescens strains to a range of heavy metals and antibiotics shows multiple resistance to nickel and cobalt, as well as to kanamycin, ampicillin and chloramphenicol. To cope with the presence of Sb and As, S. marcescens has adopted life in group mode and form biofilms to reduce their toxicity. The molecular study of the resistance mechanisms of the two strains, using cell transformation methods, reveals that the genetic determinants responsibles for the resistance of S. marcescens to metalloids are carried mainly by the chromosome.Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/biologie/KAS7638.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11472 Étude des mécanismes de résistance de bactéries endophytes isolées à partir des racines d’Hedysarum pallidum et de Lygeum spartum poussant sur des déblais de mine d’antimoine. [texte imprimé] / Mounia Kassa Laouar ép Chouikh, Auteur ; Aicha Mechakra (Née Maza), Directeur de thèse ; Oualida Rached-Mosbah, Directeur de thèse . - 09/07/2020 . - جامعة الإخوة منتوري قسنطينة, 2020 . - 183 f. ; 30 cm.
1 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Biochimie et Biologie Cellulaire et Moléculaire: Biochimie-Microbiologie appliquée bactéries endophytes métalloïdes stress oxydatif H2O2 MDA proline enzymes
antioxydantes biofilm transformation résistance bacterial endophytes metalloids oxidative stress antioxidant enzymes resistance البكتيريا الداخلية المعادن الثقيلة الإجهاد التأكسدي H2O2البرولين إنزيمات مضادات الأكسدة المقاومة التحولIndex. décimale : 570 Sciences de la vie. Biologie Résumé :
This work focuses on the study of the endophytic bacterial flora of H. pallidum and L. spartum roots, growing on the soil of mining region polluted by Sb and As, and the determination of the physiological, biochemical and molecular defense mechanisms adopted by this microflora to fight against metallic stress. The morphological and biochemical analyzes reveal a high biodiversity of this endophytic microflora. The study of the Sb and As toxicity allows the selection of two strains having the highest MICs, namely 450 mM of Sb and 175 mM of As. The molecular identification of resistant strains via 16S RNA gene sequencing shows that they are identical and belong to the Serratia marcescens species with 99% homology. The batch culture in presence of gradual Sb and As concentrations reveals a progressive decrease in bacterial growth of the two strains. Moreover, the measurement of oxidative stress parameters indicates a significant increase in the H2O2 amount, the MDA amount, the intracellular proline and even the activities of antioxidant enzymes, except at high thresholds in Sb and As. These enzymes permit the detoxification of the bacteria by elimination of the H2O2 and the other free radicals generated by metallic stress. In addition, the study of the resistance of S. marcescens strains to a range of heavy metals and antibiotics shows multiple resistance to nickel and cobalt, as well as to kanamycin, ampicillin and chloramphenicol. To cope with the presence of Sb and As, S. marcescens has adopted life in group mode and form biofilms to reduce their toxicity. The molecular study of the resistance mechanisms of the two strains, using cell transformation methods, reveals that the genetic determinants responsibles for the resistance of S. marcescens to metalloids are carried mainly by the chromosome.Note de contenu : Annexes. Diplôme : Doctorat en sciences En ligne : ../theses/biologie/KAS7638.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=11472 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité KAS/7638 KAS/7638 Thèse Bibliothèque principale Thèses Disponible
Titre : Isolation of Shewanella sp. from Algeria and characterization of a system involved in detoxification of chromate Type de document : texte imprimé Auteurs : Hiba Baaziz, Auteur ; Radia Alatou, Directeur de thèse ; Michel Fons, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 144 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Anglais (eng) Catégories : Français - Anglais
BiologieTags : Shewanella sp. chromate resistance reduction bioremediation Index. décimale : 570 Sciences de la vie. Biologie Résumé : The widespread use of the toxic heavy metal chromium (Cr) in industrial applications resulted in large quantities of Cr being discharged into the environment, causing severe contamination of global soil and water systems. Cr primarily exists in two stable forms, Cr(III) and Cr(VI). The latter is highly toxic due to its strong oxidizing nature and its high solubility. The model organism for bioremediation Shewanella oneidensis MR1 has evolved diverse resistance mechanisms to cope with chromate toxicity. The first aim of the present thesis was to study the chromate resistance and reduction mechanisms of this bacterium under semi-aerobic conditions. We showed that chrASO gene is induced by chromate and its deletion impairs the chromate resistance and reduction capacity of MR-1 strain, we confirmed that its product functions as an efflux pump to extrude chromate ions from the cytoplasm protecting cells from chromate toxicity. With cymAdeletion mutants, we revealed the involvement of the c-type cytochrome CymA in chromate resistance and reduction. We also identified a potential chromate reductase DmsA2, as well as two other proteins Fdh and DmsA1 that are potentially involved in chromate resistance and reduction in MR-1 strain. In the second part of this work, we isolated, identified and characterized two novel Mediterranean Shewanella sp. strains, S. fidelis H76 and S. algidipiscicola H111. Both strains are characterized by their great chromate resistance and their ability to reduce it efficiently even at high concentrations. Although the small size of its genome and the absence of several genes encoding enzymes known to play a role in chromate resistance and reduction, the H111 strain is the best chromate resistant strain. Interestingly, the air liquid interface biofilm (Pellicles) of both strains reduce more efficiently chromate than their freeswimming cells. Moreover, they can accumulate a significant amount of its reduced forms. These characteristics make those strains, in particular H111 strain, suitable candidates for chromate bioremediation.
Diplôme : Doctorat En ligne : ../theses/biologie/BAA7327.pdf Format de la ressource électronique : Permalink : index.php?lvl=notice_display&id=10977 Isolation of Shewanella sp. from Algeria and characterization of a system involved in detoxification of chromate [texte imprimé] / Hiba Baaziz, Auteur ; Radia Alatou, Directeur de thèse ; Michel Fons, Directeur de thèse . - جامعة الإخوة منتوري قسنطينة, 2018 . - 144 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Anglais (eng)
Catégories : Français - Anglais
BiologieTags : Shewanella sp. chromate resistance reduction bioremediation Index. décimale : 570 Sciences de la vie. Biologie Résumé : The widespread use of the toxic heavy metal chromium (Cr) in industrial applications resulted in large quantities of Cr being discharged into the environment, causing severe contamination of global soil and water systems. Cr primarily exists in two stable forms, Cr(III) and Cr(VI). The latter is highly toxic due to its strong oxidizing nature and its high solubility. The model organism for bioremediation Shewanella oneidensis MR1 has evolved diverse resistance mechanisms to cope with chromate toxicity. The first aim of the present thesis was to study the chromate resistance and reduction mechanisms of this bacterium under semi-aerobic conditions. We showed that chrASO gene is induced by chromate and its deletion impairs the chromate resistance and reduction capacity of MR-1 strain, we confirmed that its product functions as an efflux pump to extrude chromate ions from the cytoplasm protecting cells from chromate toxicity. With cymAdeletion mutants, we revealed the involvement of the c-type cytochrome CymA in chromate resistance and reduction. We also identified a potential chromate reductase DmsA2, as well as two other proteins Fdh and DmsA1 that are potentially involved in chromate resistance and reduction in MR-1 strain. In the second part of this work, we isolated, identified and characterized two novel Mediterranean Shewanella sp. strains, S. fidelis H76 and S. algidipiscicola H111. Both strains are characterized by their great chromate resistance and their ability to reduce it efficiently even at high concentrations. Although the small size of its genome and the absence of several genes encoding enzymes known to play a role in chromate resistance and reduction, the H111 strain is the best chromate resistant strain. Interestingly, the air liquid interface biofilm (Pellicles) of both strains reduce more efficiently chromate than their freeswimming cells. Moreover, they can accumulate a significant amount of its reduced forms. These characteristics make those strains, in particular H111 strain, suitable candidates for chromate bioremediation.
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