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Auteur Abderrahmane Boulahrouf |
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Affiner la 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 Streptomyces??????? ?????? ????? ???? ????? ??????? .S16 ARNr ????? 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 : https://bu.umc.edu.dz/md/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 . - [S.l.] : 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 Streptomyces??????? ?????? ????? ???? ????? ??????? .S16 ARNr ????? 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 : https://bu.umc.edu.dz/md/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 : Effets d'un herbicide de la famille des sulfonylurées sur La communauté Bactérienne d'un sol agricole, étude de cas : le chevalier OnePass Type de document : texte imprimé Auteurs : Dallel Arabet, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse ; Vincent Méjean, Directeur de thèse Editeur : constantine [Algérie] : Université Constantine 1 Année de publication : 2014 Importance : 82 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Sulfonylurées, Herbicides, Chevalier ® OnePass, Communauté bactérienne tellurique.
Sulfonylurea , herbicide , Chevalier® OnePass, Soil bacterial community
??????? ?????, ?????? ???????, ??????, ??????? ??????Index. décimale : 570 Sciences de la vie. Biologie Résumé : "Sulfonylurea herbicides are widely used on a wide range of crops to control weeds. Chevalier® OnePass
herbicide is a sulfonylurea herbicide intensively used on cereal crops in Algeria. No information is yet
available about the biodegradation of this herbicide or about its effect on the bacterial community of the soil.
In this study, we collected an untreated soil sample, and another sample was collected 1 month after
treatment with the herbicide. Using a high resolution melting DNA technique, we have shown that treatment
with Chevalier® OnePass herbicide only slightly changed the composition of the whole bacterial
community.
Two hundred fifty-nine macroscopically different clones were isolated from the untreated and treated soil
under both aerobic and microaerobic conditions. The strains were identified by sequencing a conserved
fragment of the 16S rRNA gene. The phylogenetic trees constructed using the sequencing results confirmed
that the bacterial populations were similar in the two soil samples.
Species belonging to the Lysinibacillus, Bacillus, Pseudomonas, and Paenibacillus genera were the most
abundant species found. Surprisingly, we found that among ten strains isolated from the treated soil, only six
were resistant to the herbicide.
Furthermore, bacterial overlay experiments showed that only one resistant strain (related to
Stenotrophomonas maltophilia) allowed all the sensitive strains tested to grow in the presence of the
herbicide. The other resistant strains allowed only certain sensitive strains to grow.
On the basis of these results, we propose that there must be several biodegradation pathways for this
sulfonylurea herbicide."
Diplôme : Doctorat En ligne : ../theses/biologie/ARA6551.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9665 Effets d'un herbicide de la famille des sulfonylurées sur La communauté Bactérienne d'un sol agricole, étude de cas : le chevalier OnePass [texte imprimé] / Dallel Arabet, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse ; Vincent Méjean, Directeur de thèse . - constantine (Route ain el bey, Algérie) : Université Constantine 1, 2014 . - 82 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Sulfonylurées, Herbicides, Chevalier ® OnePass, Communauté bactérienne tellurique.
Sulfonylurea , herbicide , Chevalier® OnePass, Soil bacterial community
??????? ?????, ?????? ???????, ??????, ??????? ??????Index. décimale : 570 Sciences de la vie. Biologie Résumé : "Sulfonylurea herbicides are widely used on a wide range of crops to control weeds. Chevalier® OnePass
herbicide is a sulfonylurea herbicide intensively used on cereal crops in Algeria. No information is yet
available about the biodegradation of this herbicide or about its effect on the bacterial community of the soil.
In this study, we collected an untreated soil sample, and another sample was collected 1 month after
treatment with the herbicide. Using a high resolution melting DNA technique, we have shown that treatment
with Chevalier® OnePass herbicide only slightly changed the composition of the whole bacterial
community.
Two hundred fifty-nine macroscopically different clones were isolated from the untreated and treated soil
under both aerobic and microaerobic conditions. The strains were identified by sequencing a conserved
fragment of the 16S rRNA gene. The phylogenetic trees constructed using the sequencing results confirmed
that the bacterial populations were similar in the two soil samples.
Species belonging to the Lysinibacillus, Bacillus, Pseudomonas, and Paenibacillus genera were the most
abundant species found. Surprisingly, we found that among ten strains isolated from the treated soil, only six
were resistant to the herbicide.
Furthermore, bacterial overlay experiments showed that only one resistant strain (related to
Stenotrophomonas maltophilia) allowed all the sensitive strains tested to grow in the presence of the
herbicide. The other resistant strains allowed only certain sensitive strains to grow.
On the basis of these results, we propose that there must be several biodegradation pathways for this
sulfonylurea herbicide."
Diplôme : Doctorat En ligne : ../theses/biologie/ARA6551.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9665 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité ARA/6551 ARA/6551 Thèse Bibliothèque principale Thèses Disponible
Titre : "Étude des infections causées par les actinomycètes aérobie autres que les mycobactéries dans la région de Constantine " Type de document : texte imprimé Auteurs : Lamia Oulmi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse Editeur : constantine [Algérie] : Université Constantine 1 Année de publication : 2014 Importance : 184 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : "actinomycètes aérobies pathogènes, Nocardiopsaceae,
Pseudonocardiaceae, Micromonosporaceae, Thermomonosporaceae,
Tsukamurellaceae, diagnostic bactériologique, pyroséquençages, MALDI-TOF."
"pathogenic aerobic actinomycetes, Nocardiopsaceae, Pseudonocardiaceae,
Micromonosporaceae, Tsukamurellaceae, Thermomonosporaceae, bactériological
diagnostic, pyrosequencing, MALDI-TOF."
????????????? ????????? ??????? ???????????? PCR ?MALDI-TOF TsukamurellaIndex. décimale : 570 Sciences de la vie. Biologie Résumé : "Actinomycetes are Gram-stain-positive. Ubiquitous, they live as saprophyte in the soil.
Although they are rarely encountered in clinical practice, they have great potential and
cause serious human infections.
Forty-two strains of aerobic actinomycetes (except mycobacteria) were isolated from
3682 clinical specimens patients from Benbadis Hospital of Constantine. The diversity
and identification of some representative isolates were determined by a polyphasic
approach (phenotypic, genotypic and phylogenetic informations).
Phylogenetic analysis of the isolates allowed to classify them in the phylum of
Actinobacteria, to the families of Nocadiopsaceae, Pseudonocardiaceae,
Micromonosporaceae, Tsukamurellaceae, and Thermomonosporaceae. They are
affiliated to seven different genera, Nocardiopsis (53.33%), Pseudonocardia (13.33%),
Murinocardiopsis (6.66%), Tsukamurella (6.66%), Actinomadura (6.66),
Micromonospora (6.66) et Saccharopolyspora (6.66%).
Approach by proteomics analysis of mass spectrometry MALDI-TOF has been
validated and optimized for the identification and classification of bacteria of the genus
Tsukamurella. Through the MLST method and the amplification of four genes (lepA,
rpoA, rpo B and ftsZ) and the technique of mass spectrometry we were able to conclude
that isolate 1534 is probably a new species of Tsukamurella. Furthermore, sequencing
of the complete genome of this isolate was done by two sequencing techniques, the
shotgun method and 3-kb paired-end."
Diplôme : Doctorat en sciences En ligne : ../theses/biologie/OUL6602.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9715 "Étude des infections causées par les actinomycètes aérobie autres que les mycobactéries dans la région de Constantine " [texte imprimé] / Lamia Oulmi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse . - constantine (Route ain el bey, Algérie) : Université Constantine 1, 2014 . - 184 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : "actinomycètes aérobies pathogènes, Nocardiopsaceae,
Pseudonocardiaceae, Micromonosporaceae, Thermomonosporaceae,
Tsukamurellaceae, diagnostic bactériologique, pyroséquençages, MALDI-TOF."
"pathogenic aerobic actinomycetes, Nocardiopsaceae, Pseudonocardiaceae,
Micromonosporaceae, Tsukamurellaceae, Thermomonosporaceae, bactériological
diagnostic, pyrosequencing, MALDI-TOF."
????????????? ????????? ??????? ???????????? PCR ?MALDI-TOF TsukamurellaIndex. décimale : 570 Sciences de la vie. Biologie Résumé : "Actinomycetes are Gram-stain-positive. Ubiquitous, they live as saprophyte in the soil.
Although they are rarely encountered in clinical practice, they have great potential and
cause serious human infections.
Forty-two strains of aerobic actinomycetes (except mycobacteria) were isolated from
3682 clinical specimens patients from Benbadis Hospital of Constantine. The diversity
and identification of some representative isolates were determined by a polyphasic
approach (phenotypic, genotypic and phylogenetic informations).
Phylogenetic analysis of the isolates allowed to classify them in the phylum of
Actinobacteria, to the families of Nocadiopsaceae, Pseudonocardiaceae,
Micromonosporaceae, Tsukamurellaceae, and Thermomonosporaceae. They are
affiliated to seven different genera, Nocardiopsis (53.33%), Pseudonocardia (13.33%),
Murinocardiopsis (6.66%), Tsukamurella (6.66%), Actinomadura (6.66),
Micromonospora (6.66) et Saccharopolyspora (6.66%).
Approach by proteomics analysis of mass spectrometry MALDI-TOF has been
validated and optimized for the identification and classification of bacteria of the genus
Tsukamurella. Through the MLST method and the amplification of four genes (lepA,
rpoA, rpo B and ftsZ) and the technique of mass spectrometry we were able to conclude
that isolate 1534 is probably a new species of Tsukamurella. Furthermore, sequencing
of the complete genome of this isolate was done by two sequencing techniques, the
shotgun method and 3-kb paired-end."
Diplôme : Doctorat en sciences En ligne : ../theses/biologie/OUL6602.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=9715 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité OUL/6602 OUL/6602 Thèse Bibliothèque principale Thèses Disponible
Titre : Étude de molécules antibiotiques secrétées par des souches appartenant au genre Streptomyces, isolées de Sebkha. Type de document : texte imprimé Auteurs : Faiza Boughachiche, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse Editeur : Constantine : Université Mentouri Constantine Année de publication : 2012 Importance : 150 f. Format : 31 cm. Note générale : Doctorat en sciences
2 copies imprimées disponiblesLangues : Français (fre) Catégories : Français - Anglais
BiologieTags : Sebkha actinomycètes Streptomyces antibiotique analyse structurale Index. décimale : 570 Sciences de la vie. Biologie Diplôme : Doctorat en sciences En ligne : ../theses/biologie/BOU6205.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=6169 Étude de molécules antibiotiques secrétées par des souches appartenant au genre Streptomyces, isolées de Sebkha. [texte imprimé] / Faiza Boughachiche, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse . - Constantine : Université Mentouri Constantine, 2012 . - 150 f. ; 31 cm.
Doctorat en sciences
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Sebkha actinomycètes Streptomyces antibiotique analyse structurale Index. décimale : 570 Sciences de la vie. Biologie Diplôme : Doctorat en sciences En ligne : ../theses/biologie/BOU6205.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=6169 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BOU/6205 BOU/6205 Thèse Bibliothèque principale Thèses Disponible
Titre : Identification polyphasique des souches d’actinobactéries isolées d’échantillons de sols semi-arides : Caractérisation structurale des antibiotiques produits. Type de document : texte imprimé Auteurs : Nassima Leulmi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 174 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Français (fre) Catégories : Français - Anglais
BiologieTags : Actinobactéries Streptomyces sols semi-arides antibiotiques polyéthers ionophores cytotoxicité Actinobacteria Semi-arid soils Antibiotics ionophoric polyethers Cytotoxicity ??????????????? ??? ??? ???? ???????? ??????? polyéthers ionophores ?????? ?????? Index. décimale : 570 Sciences de la vie. Biologie Résumé : Actinobacteria are a group of filamentous bacteria, mainly inhabit the soil. They are known for producing a wide variety of bioactive molecules, especially antibiotics. Is in this context that our research work focused. A total of 99 isolates were recovered from a semi-arid soi,collected from; rhizospheric associated soil (Khenchela), mountain soil (Mount chélia region, khenchela) and Sebkha soil (Oum El bouaghi). Three strains (SF10, SFKH4 and SFKH10), were selected, based on preliminary screening for antimicrobial activity. The isolates were identified as belonging to the genus Streptomyces, based on phenotypic and chemotaxonomic study. Phylogenetic analysis revealed that the strains SF10, SFKH4 and SFKH10 were most closely related to Streptomyces youssoufiensis, Streptomyces spororaveus and Streptomyces coeruleorubidus with a pairwise 16S rRNA gene sequence similarity of 99, 8, 99 % and 99%. Ethyl acetate extracts provied by the culture of the strains on solid culture were tested for their antimicrobial activity against the test microorganisms. The structure elucidation of the biologically active molecules, purified by different chromatographic methods, was carried out by coupling several techniques of mass
spectrometry and Nuclear Magnetic Resonance (1H NMR, 13C NMR, MS, MS tandem, IR and UV-Visible). Streptomyces youssoufiensis SF10 strain produced several molecules belonging to ionophoric polyethers family, abierixin, nigericin, epinigericin, and the newly isolated grisorixin methyl ester. Moreover, only one molecule, belonging to macrotetrolides family (dinactin), was obtained from Streptomyces coeruleorubidus SFKH10 strain. In addition, the partial characterization of the molecules secreted by S. spororaveus SFKH4 strain has shown its capacity to produce a large variety of complexes compounds having high molecular weight. The presence of epimeric forms of nigericin/epinigericin and grisorixin/epigrisorixin has spurred DFT (Density Functional Theory) computational calculations. This analysis was able to provide the relative stability of the most favored epimers. This consideration is of general interest and can be applied to the wide class of naturally occurring polycyclic polyethers. On the other hand, the study of the cytotoxicity of the purified and identified molecules revealed that both nigericin and grisorixin methyl ester showed to affect glioblastoma stem cells proliferation in a dose-dependent manner, with a higher activity for the more lipophilic grisorixin methyl ester (IC50 values of 3.85 and 3.05 μM for VIPI and COMI humain glioblastoma stem cells, respectively). In conclusion, the present study has revealed the potential of semi-arid Algerian ecosystems as a good source for bioactives molecules-producing actinobacteria, specialy Streptomyces youssoufienisis SF10 strain whose secondary metabolites profile has not been studied so far by bioguided method. The clear antiproliferative activity of grisorixin methyl ester on glioblastoma stem cells represents a promising starting point aimed to the development of new drug candidates in the treatment of glioblastoma multiforme.
Diplôme : Doctorat en sciences Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11029 Identification polyphasique des souches d’actinobactéries isolées d’échantillons de sols semi-arides : Caractérisation structurale des antibiotiques produits. [texte imprimé] / Nassima Leulmi, Auteur ; Abderrahmane Boulahrouf, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 174 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Français (fre)
Catégories : Français - Anglais
BiologieTags : Actinobactéries Streptomyces sols semi-arides antibiotiques polyéthers ionophores cytotoxicité Actinobacteria Semi-arid soils Antibiotics ionophoric polyethers Cytotoxicity ??????????????? ??? ??? ???? ???????? ??????? polyéthers ionophores ?????? ?????? Index. décimale : 570 Sciences de la vie. Biologie Résumé : Actinobacteria are a group of filamentous bacteria, mainly inhabit the soil. They are known for producing a wide variety of bioactive molecules, especially antibiotics. Is in this context that our research work focused. A total of 99 isolates were recovered from a semi-arid soi,collected from; rhizospheric associated soil (Khenchela), mountain soil (Mount chélia region, khenchela) and Sebkha soil (Oum El bouaghi). Three strains (SF10, SFKH4 and SFKH10), were selected, based on preliminary screening for antimicrobial activity. The isolates were identified as belonging to the genus Streptomyces, based on phenotypic and chemotaxonomic study. Phylogenetic analysis revealed that the strains SF10, SFKH4 and SFKH10 were most closely related to Streptomyces youssoufiensis, Streptomyces spororaveus and Streptomyces coeruleorubidus with a pairwise 16S rRNA gene sequence similarity of 99, 8, 99 % and 99%. Ethyl acetate extracts provied by the culture of the strains on solid culture were tested for their antimicrobial activity against the test microorganisms. The structure elucidation of the biologically active molecules, purified by different chromatographic methods, was carried out by coupling several techniques of mass
spectrometry and Nuclear Magnetic Resonance (1H NMR, 13C NMR, MS, MS tandem, IR and UV-Visible). Streptomyces youssoufiensis SF10 strain produced several molecules belonging to ionophoric polyethers family, abierixin, nigericin, epinigericin, and the newly isolated grisorixin methyl ester. Moreover, only one molecule, belonging to macrotetrolides family (dinactin), was obtained from Streptomyces coeruleorubidus SFKH10 strain. In addition, the partial characterization of the molecules secreted by S. spororaveus SFKH4 strain has shown its capacity to produce a large variety of complexes compounds having high molecular weight. The presence of epimeric forms of nigericin/epinigericin and grisorixin/epigrisorixin has spurred DFT (Density Functional Theory) computational calculations. This analysis was able to provide the relative stability of the most favored epimers. This consideration is of general interest and can be applied to the wide class of naturally occurring polycyclic polyethers. On the other hand, the study of the cytotoxicity of the purified and identified molecules revealed that both nigericin and grisorixin methyl ester showed to affect glioblastoma stem cells proliferation in a dose-dependent manner, with a higher activity for the more lipophilic grisorixin methyl ester (IC50 values of 3.85 and 3.05 μM for VIPI and COMI humain glioblastoma stem cells, respectively). In conclusion, the present study has revealed the potential of semi-arid Algerian ecosystems as a good source for bioactives molecules-producing actinobacteria, specialy Streptomyces youssoufienisis SF10 strain whose secondary metabolites profile has not been studied so far by bioguided method. The clear antiproliferative activity of grisorixin methyl ester on glioblastoma stem cells represents a promising starting point aimed to the development of new drug candidates in the treatment of glioblastoma multiforme.
Diplôme : Doctorat en sciences Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11029 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité LEU/7380 LEU/7380 Thèse Bibliothèque principale Thèses Disponible
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