Bacteriocins produced by lactic acid bacteria offer potential as tools for ensuring food safety a... more Bacteriocins produced by lactic acid bacteria offer potential as tools for ensuring food safety and quality. The current research aimed to identify and characterize a bacteriocin-like substance produced by Pidiococcus pentocaseus sp. isolated from Algerian goat's milk. The production of this antimicrobial during the stationary growth phase, destruction of antimicrobial activity by proteolytic enzymes indicated that the antimicrobial is a bacteriocin. T h e b a c t e r i o c i n p r o v e d t o b e a c t i v e a g a i n s t g r a m p o s i t i v e b a c t e r i a l i k e i s o l a t e s o f Staphylococcus aureus, and was heat labile as the antimicrobial activity was destroyed by heating after 120°C for 15 min. Bacteriocin activity was stable after three months of storage at 4°C and-20°C, for 75 min of exposure to UV light and at pH values between 2.0 and 6.0. This bacteriocin was also found to lyse sensitive cells. Results revealed that an increase in bacteriocins activity of the strain against Staphylococcus aureus on increasing the concentration of NaCl and KCl up to 5% and in the presence of spices 5%. Results presented here support the idea that the bacteriocin may propose some industrial advantage that renders it as a good natural food biopreservative candidate.
Résumé. L’utilisation des extraits de plantes est prouvée récemment comme étant une méthode alter... more Résumé. L’utilisation des extraits de plantes est prouvée récemment comme étant une méthode alternative dans le biocontrol de plusieurs maladies cryptogamiques. Le présent travail est porté sur l’évaluation de l’activité antifongique de l’huile essentielle de la cannelle sur quelques champignons phytopathogènes, il représente une contribution dans la recherche des moyens de lutte biologique contre les maladies de l’helminthosporiose, et des pourritures racinaires qui causent des dégâts très important en céréaliculture. L’extraction de l’huile essentielle de la cannelle a été effectuée par hydrodistilation dont la teneur en essence végétale est plus ou moins importante (1,5%). L’effet de l’huile essentielle a été testé sur la croissance mycélienne, et la sporulation de quatre espèces fongiques isolées à partir des feuilles et des racines d’orge (Hordeum vulgare L.) présentant des symptômes de maladies : Drechslera teres, agent de la rayure réticulée de l’orge. D. graminea (la strie folaire), Bipolaris sorokiniana (taches helminthosporiennes) et Fusarium graminearum, agent des pourritures racinaires. D’après les résultats obtenus, touts les isolats testés se sont révélés sensibles à l’essence végétale étudiée, avec des concentrations minimales inhibitrices (CMI) allant de 1 à 8μg/ml. Ces résultats présentent un intérêt pour l’utilisation des huiles essentielles dans des applications phytosanitaire comme un procédé de lutte biologique basé sur les substances naturelles. Mots clés: Cannelle – Huile essentielle- Antifongique- Champignons phytopathogènes
The antifungal activity of ten plants extracts was tested in controlling Pyrenophora teres the ca... more The antifungal activity of ten plants extracts was tested in controlling Pyrenophora teres the causal organism of net blotch of Barley in vitro and in vivo. Effects of the aqueous extracts varied depending on concentrations. In in vitro study the aqueous extracts of Anacyclus valentinus and Tetraclinis articulate at 1500 ppm caused highest reduction of mycelia growth of P.teres(72.27 and 87.05 % respectively), while extracts of Mentha pepirita and Foeniculum vulgare caused the lowest inhibition of the pathogen. In in vivo experiments the plants extracts were tested for their preventive and curative efficacy against net blotch. Barley plants were treated either aqueous extracts 1 day before or2 days after artificial inoculation. The highest reduction of diseases severity was achieved by the extract of Tetraclinis articulata. The same extracts were then tested as seed treatments, against seed-borne fungi. The best control against barley seed mycoflora was obtained with the extract of Inulavis cosa(72.8%). Results revealed that the selected plant extracts were active on both Pyrenophora teres in vitro, on disease severity in vivo and can be used as potential seed treatments for net blotch disease control.
Barley net blotch, caused by Pyrenophora teres f. teres (Ptt), is one of the most important folia... more Barley net blotch, caused by Pyrenophora teres f. teres (Ptt), is one of the most important foliar diseases in north western Algeria. The disease causes appreciable yield losses under favorable environmental conditions. Studies on pathogen variability and distribution of virulence in Ptt are essential to identify effective sources of resistance to this disease. In this study, pathogenic variability in 48 isolates of Ptt, collected from different barley-growing areas of northwestern Algeria, were evaluated using 22 barley genotypes as differential hosts. Trials carried out under controlled conditions confirmed the large variation in the virulence of this fungus. The genotypes exhibited variability in response ranging from complete resistance to high susceptibility. This is the first report of pathogenic variability in Ptt in north western Algeria. The 48 isolates tested were further differentiated into 12 pathotypes. Eight differential cultivars were resistant to all isolates tested, but others were susceptible to one or more of the isolates. The variability in the pathogen and the resistance identified in some genotypes used in this study are being investigated further to develop superior, adapted germplasm for use in barley breeding programs in north western Algeria.
Bacteriocins produced by lactic acid bacteria offer potential as tools for ensuring food safety a... more Bacteriocins produced by lactic acid bacteria offer potential as tools for ensuring food safety and quality. The current research aimed to identify and characterize a bacteriocin-like substance produced by Pidiococcus pentocaseus sp. isolated from Algerian goat's milk. The production of this antimicrobial during the stationary growth phase, destruction of antimicrobial activity by proteolytic enzymes indicated that the antimicrobial is a bacteriocin. T h e b a c t e r i o c i n p r o v e d t o b e a c t i v e a g a i n s t g r a m p o s i t i v e b a c t e r i a l i k e i s o l a t e s o f Staphylococcus aureus, and was heat labile as the antimicrobial activity was destroyed by heating after 120°C for 15 min. Bacteriocin activity was stable after three months of storage at 4°C and-20°C, for 75 min of exposure to UV light and at pH values between 2.0 and 6.0. This bacteriocin was also found to lyse sensitive cells. Results revealed that an increase in bacteriocins activity of the strain against Staphylococcus aureus on increasing the concentration of NaCl and KCl up to 5% and in the presence of spices 5%. Results presented here support the idea that the bacteriocin may propose some industrial advantage that renders it as a good natural food biopreservative candidate.
Résumé. L’utilisation des extraits de plantes est prouvée récemment comme étant une méthode alter... more Résumé. L’utilisation des extraits de plantes est prouvée récemment comme étant une méthode alternative dans le biocontrol de plusieurs maladies cryptogamiques. Le présent travail est porté sur l’évaluation de l’activité antifongique de l’huile essentielle de la cannelle sur quelques champignons phytopathogènes, il représente une contribution dans la recherche des moyens de lutte biologique contre les maladies de l’helminthosporiose, et des pourritures racinaires qui causent des dégâts très important en céréaliculture. L’extraction de l’huile essentielle de la cannelle a été effectuée par hydrodistilation dont la teneur en essence végétale est plus ou moins importante (1,5%). L’effet de l’huile essentielle a été testé sur la croissance mycélienne, et la sporulation de quatre espèces fongiques isolées à partir des feuilles et des racines d’orge (Hordeum vulgare L.) présentant des symptômes de maladies : Drechslera teres, agent de la rayure réticulée de l’orge. D. graminea (la strie folaire), Bipolaris sorokiniana (taches helminthosporiennes) et Fusarium graminearum, agent des pourritures racinaires. D’après les résultats obtenus, touts les isolats testés se sont révélés sensibles à l’essence végétale étudiée, avec des concentrations minimales inhibitrices (CMI) allant de 1 à 8μg/ml. Ces résultats présentent un intérêt pour l’utilisation des huiles essentielles dans des applications phytosanitaire comme un procédé de lutte biologique basé sur les substances naturelles. Mots clés: Cannelle – Huile essentielle- Antifongique- Champignons phytopathogènes
The antifungal activity of ten plants extracts was tested in controlling Pyrenophora teres the ca... more The antifungal activity of ten plants extracts was tested in controlling Pyrenophora teres the causal organism of net blotch of Barley in vitro and in vivo. Effects of the aqueous extracts varied depending on concentrations. In in vitro study the aqueous extracts of Anacyclus valentinus and Tetraclinis articulate at 1500 ppm caused highest reduction of mycelia growth of P.teres(72.27 and 87.05 % respectively), while extracts of Mentha pepirita and Foeniculum vulgare caused the lowest inhibition of the pathogen. In in vivo experiments the plants extracts were tested for their preventive and curative efficacy against net blotch. Barley plants were treated either aqueous extracts 1 day before or2 days after artificial inoculation. The highest reduction of diseases severity was achieved by the extract of Tetraclinis articulata. The same extracts were then tested as seed treatments, against seed-borne fungi. The best control against barley seed mycoflora was obtained with the extract of Inulavis cosa(72.8%). Results revealed that the selected plant extracts were active on both Pyrenophora teres in vitro, on disease severity in vivo and can be used as potential seed treatments for net blotch disease control.
Barley net blotch, caused by Pyrenophora teres f. teres (Ptt), is one of the most important folia... more Barley net blotch, caused by Pyrenophora teres f. teres (Ptt), is one of the most important foliar diseases in north western Algeria. The disease causes appreciable yield losses under favorable environmental conditions. Studies on pathogen variability and distribution of virulence in Ptt are essential to identify effective sources of resistance to this disease. In this study, pathogenic variability in 48 isolates of Ptt, collected from different barley-growing areas of northwestern Algeria, were evaluated using 22 barley genotypes as differential hosts. Trials carried out under controlled conditions confirmed the large variation in the virulence of this fungus. The genotypes exhibited variability in response ranging from complete resistance to high susceptibility. This is the first report of pathogenic variability in Ptt in north western Algeria. The 48 isolates tested were further differentiated into 12 pathotypes. Eight differential cultivars were resistant to all isolates tested, but others were susceptible to one or more of the isolates. The variability in the pathogen and the resistance identified in some genotypes used in this study are being investigated further to develop superior, adapted germplasm for use in barley breeding programs in north western Algeria.
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Papers by boungab Karima
symptômes de maladies : Drechslera teres, agent de la rayure réticulée de l’orge. D. graminea (la strie folaire), Bipolaris sorokiniana (taches helminthosporiennes) et Fusarium graminearum, agent des pourritures racinaires. D’après les résultats obtenus, touts les isolats testés se sont révélés sensibles à l’essence végétale étudiée, avec des concentrations minimales inhibitrices (CMI) allant de 1 à 8μg/ml.
Ces résultats présentent un intérêt pour l’utilisation des huiles essentielles dans des applications phytosanitaire comme un procédé de lutte biologique basé sur les substances naturelles.
Mots clés: Cannelle – Huile essentielle- Antifongique- Champignons phytopathogènes
symptômes de maladies : Drechslera teres, agent de la rayure réticulée de l’orge. D. graminea (la strie folaire), Bipolaris sorokiniana (taches helminthosporiennes) et Fusarium graminearum, agent des pourritures racinaires. D’après les résultats obtenus, touts les isolats testés se sont révélés sensibles à l’essence végétale étudiée, avec des concentrations minimales inhibitrices (CMI) allant de 1 à 8μg/ml.
Ces résultats présentent un intérêt pour l’utilisation des huiles essentielles dans des applications phytosanitaire comme un procédé de lutte biologique basé sur les substances naturelles.
Mots clés: Cannelle – Huile essentielle- Antifongique- Champignons phytopathogènes