CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Lactobacillus johnsonii CRL1647 functional properties
Autor/es:
TORRES M. J.; APELLA M. C.; AUDISIO M. C.
Lugar:
San Miguel de Tucumán
Reunión:
Simposio; III Internacional Symposium on Lactic Acid Bacteria and III Argentinean LAB Net Meeting; 2009
Institución organizadora:
CONICET, ANCyT, Ministerio de Salud Pública, SIDETEC-Tucumán
Resumen:
Lactobacillus johnsonii CRL1647 was isolated from the gut of a honeybee from Salta, Argentina. This strain showed in vitro antimicrobial activity against Paenibacillus larvae and Ascosphaera apis, ethiological agents of American foulbrood and ascosphaerosis in Apis mellifera L., respectively. The aim of this work was to study functional properties of this microorganism strain that may contribute to design a bee probiotic supplement. L. johnsonii CRL1647 cells were grown in MRS broth at 37 ºC for 24 h under microaerophilic conditions. The auto-aggregation and co-aggregation analyses related with surface properties were determined. In the first case, the changes in absorbance at 600 nm were determined and expresed as percentage of auto-aggregation. Candida sp. C6184 and C22 strains were used to evaluate the co-aggregation ability of this lactobacillus. The chemical nature of the molecules involved in the surface adsorption phenomena was analyzed by treatment of L. johnsonii cells with solutions of 1 mg mL-1 of trypsin and pepsin at 37 ºC for 1 h, lipase and sodium m-periodate at 25 ºC for 1 h, and heated to 100 ºC for 15 min. In addition, the sensitivity of this lactic acid bacterium to colmesan, oxytetracycline and flumevar (antibiotics used in beekeeping in Argentina) was determined according to the agar diffusion method and minimum inhibitory concentration (MIC) was calculated. The L. johnsonii CRL1647 cells showed 85% auto-aggregation, corroborated by optical microscope (100X) observation of cultures of this bacterium that revealed bacilli grouped in palisade The co-aggregation capability of this strain with Candida sp. C6184 and C22 strains was high (72 and 88 %, respectively). A significant decrease was observed both in autoaggregation (5%) and co-aggregation (16%) only when the lactobacilli cells were treated with a solution of trypsin. This result indicates that in the superfical interaction between lactobacilli cells and them with Candida cells, one molecule of peptidic nature could be involved. Besides, L. johnsonii was highly sensitive to oxytetracycline and colmesan (MIC: 1.25 ´ 10-4 and 6.25 ´10-3 g mL-1 respectively), while it showed a certain resistance (MIC: 0.25 g mL-1) to fllumevar. The functional properties of L. johnsonii CRL1647 studied will help to evaluate in vivo its anti-Paenilbacillus larvae and/or anti-Ascosphaera apis effects in a near future.