Influence of chemical and physical conditions on the production of bacteriocin by Aeromonas hydrophila

Aeromonas hydrophila have been isolated as a cause of a cute gastroenteritis in 23 (5.6%) of 410 patients. Other bacterial enteropathogens have been isolated from 387 patients with diarrhea, were 19 different strains. A. hydrophila occurred more commonly in children with acute diarrhea, the results showed that 18(78.26%) isolates of A. hydrophila found in children under 10 years old ,distributed to 10(43.47%) in male and 8(34.78%) in female ,and in adults with diarrhea 5 (21.73%). In the other hand, we noticed frequency of isolation was higher in male 14(60.86%) when compared with 9(39.14%) in female. Six strains of A. hydrophila have been observed to have bacteriocin activity against 12 of 23 different A. hydrophila ,as well as Staphylococcus aureas, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacea and Shigella dysenteria. The results showed Bacteriocin-like substances (BLS11) had isoinhibitory activity on 10 same A. hydrophila species and heteroinhibitory activity effects on all pathogenic bacterial strains used, while BLS5 showed isoinhibitory activity on 2 same A. hydrophila species and heteroinhibitory activity by effecting on gram negative only, and BLS3& BLS12 showed activity on E. coli isolates only, and none of BLS1& BLS10(isoinhibitory activity on 1 A.hydrophila respectively) had effect on all pathogenic bacteria. Among the standard laboratory media used Brain Heart Infusion broth (BHI) showed the maximum production and poor yields resulted from growth in Peptone Glyserol (PG) and Nutrient broth. We selected BLS11 to their wide range effect on same species and enteric pathogenic strains, to study the Influence of chemical and physical conditions on the production of BLS by A.hydrophila. The BLS11 preparations from A.hydrophila11 strains of A. hydrophila were tolerant to all three treatments of surfactant. In the other hand, effect of organic acid on BLS production BLS11 has been studied and showed no remarkable difference in zone of inhibition when used acetone as affecter element, while both of isopropanol and ethanol have narrow inhibition zone range when compared with control strain. These results indicated that most A. hydrophila might be harboring plasmid mediated bacteriocin like substance, and there are no relation between BLS production and number of plasmid bands present in bacteria

Mechanistic studies on δ-aminolevulinic acid uptake and efflux in a mammary adenocarcinoma cell line

δ-aminolevulinic acid (ALA) is the precursor in the biosynthesis of porphyrins. The knowledge of both the regulation of ALA entrance and efflux from the cells and the control of porphyrin biosynthesis is essential to improve ALA-mediated photodynamic therapy. In this work, we studied the regulation of ALA uptake and efflux by endogenously accumulated ALA and/or porphyrins in murine mammary adenocarcinoma cells. Under our set of conditions, the haem synthesis inhibitor succinyl acetone completely prevented porphobilinogen and porphyrin synthesis from ALA, and led to an increase in the intracellular ALA pool. However, neither intracellular ALA nor porphyrin pools regulate ALA uptake or efflux during the first 15 min of the process. Based on temperature dependence data, ALA but not γ-aminobutyric acid (GABA) efflux is mediated by a diffusion mechanism. Moreover, the addition of extracellular GABA not only did not influence the rate of ALA efflux but on the contrary it affected ALA uptake, showing the contribution of a saturable mechanism for the uptake, but not for the efflux of ALA from the cells. © 2003 Cancer Research UK.Fil:Correa García, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Casas, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Perotti, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Batlle, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Bermúdez Moretti, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Sulphate ion dynamics in a-alums studied by esr at high pressures

The variation of zero-field splitting and linewidth of Cr3+ ion in KCr and KAI alums with hydrostatic pressure and with temperature is investigated. A model for the apparent phase transition is proposed on the basis of the reorientational motion of the SO2-4 groups