Artículos, informes y presentaciones en Congresos
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Examinando Artículos, informes y presentaciones en Congresos por Autor "Alippi, Adriana Mónica"
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Acceso Abierto HiCrome Bacillus agar for presumptive identification of Bacillus and related species isolated from honey samples(2019) Alippi, Adriana Mónica; Abrahamovich, ElianaThis study aimed to evaluate the performance of Hicrome Bacillus™ agar for isolation and rapid identification of the aerobic spore-forming bacteria most frequently found in honey samples. A collection of 197 bacterial isolates of Bacillus, Brevibacillus, Lysinibacillus, Paenibacillus, and Rummeliibacillus belonging to different species that have been reported in honey were screened for their abilities to grow and for their colony colors and medium appearance in HiCrome Bacillus agar. Also, 21 strains from culture collections were used for comparison and quality controls. A flowchart utilizing a combination of colony and media characteristics in the chromogenic medium and a set of simple biochemical and morphological tests were elaborated for quick presumptive identification. A procedure for direct isolation from honey samples was developed. In conclusion, HiCrome Bacillus agar in combination with simple microbiological tests was highly useful for rapid and reliable identification of most Bacillus, Brevibacillus, Lysinibacillus and Paenibacillus species commonly found in honey samples facilitating isolation from polymicrobial honey. - Artículo
Acceso Abierto Potential of spore-forming bacteria as biocontrol agents of wheat foliar diseases under laboratory and greenhouse conditions(2000) Alippi, Adriana Mónica; Perelló, Analía; Sisterna, Marina Noemí; Greco, Nancy Mabel; Cordo, Cristina AliciaThe potential of Bacillus subtilis, Bacillus cereus, Bacillus licheniformis, Bacillus pumilus, Brevibacillus laterosporus and Paenibacillus polymyxa as biocontrol agents of four foliar necrotrophic pathogens of wheat in Argentina has been evaluated. The following assays were used: (a) effect of the bacterial antagonists on fungal growth in the central disk test with paired cultures, (b) effect of the antagonists on the germination of fungal spores in the paired suspension assay, and (c) reduction of disease severity in greenhouse experiments. The observed effects were specific for the antagonist-pathogen combination investigated. In the paired culture test, most of the bacterial antagonists inhibited the mycelial growth of the four pathogens tested at 14 days of the evaluation. B. licheniformis showed the best results for controlling Septoria tritici and Drechslera tritici-repentis whereas it was the worst against Bipolaris sorokiniana. In the case of Alternaria triticimaculans, the best were B. laterosporus, P. polymyxa and B. licheniformis. Microscopic examination of excised pieces of the fungal colony perimeters showed clear differences among treatments and controls in hyphal morphology (plasmolysis and vacuolation of hyphae, irregular texture in the cytoplasm, formation of chlamydospores). In the central disk test, mycelial necrosis of A. triticimaculans was induced by B. laterosporus, P. polymyxa and B. pumilus. Similar results were obtained with B. sorokiniana in the presence of B. licheniformis and B. subtilis and D. tritici-repentis with B. pumilus. In some combinations, the presence of inhibition haloes or bacterial chemotaxis were observed. In the paired suspension assay, all the bacteria except B. cereus, inhibited the conidial germination of S. tritici. Only P. polymyxa, B. licheniformis and B. laterosporus inhibited the conidial germination of A. triticimaculans, B. laterosporus being the most effective. Although all the bacteria inhibited the conidial germination of B. sorokiniana, the most efficient were B. licheniformis, B. cereus and B. laterosporus. In greenhouse experiments, P. polymyxa and B. cereus were the most efficient to reduce disease severities produced by S. tritici and A. triticimaculans; on the contrary, these bacteria were not effective against B. sorokiniana and D. tritici-repentis. B. laterosporus BLA 170 showed a good behaviour against all the fungal pathogens, particularly for D. tritici-repentis and B. sorokiniana. This is the first report on the efficacy of B. laterosporus against fungal wheat pathogens.