BACTERIOCINS OF Lactobacillus LF221 STRAIN | BACTERIOCINI SEVA Lactobacillus LF221

Inglés. LF221 strain is a Lactobacillus isolate from a baby’s faeces that was previously found to produce bacteriocin(s) with inhibitory activity against a wide range of bacterial species including some pathogenic and food-spoilage (Bacillus cereus, Clostridium sp., Listeria innocua, Staphylococcus aureus). Isoelectric point and molecular mass of bacteriocin complex and subunits were estimated. Precipitation with ammonium sulphate, cation exchange chromatography, C8 hydrophobic interaction chromatography and reverse-phase FPLC chromatography were used to isolate bacteriocins from the supernatant of MRS culture. Amino acid composition and partial N-terminal amino acid sequences of two isolated bacteriocins were determined. Bacteriocins were present in MRS supernatant as aggregates with Mw>150.000 and pI 5.1-5.3, while Mw of subunits was 3500-5000. A high content of glycin and alanin was observed for both bacteriocins. The N-terminal amino acid sequences showed little similarity with those of other bacteriocins. Acidocins LF221 A and B appear to belong to the II class of LAB bacteriocins.

Esloveno. Za sev LF221, izolat Lactobacillus iz blata dojenčka, je bilo že ugotovljeno, da proizvaja bakteriocin(e) z zaviralno aktivnostjo proti vrsti bakterij, tudi nekaterih patogenih in kvarljivcev (Bacillus cereus, Clostridium sp., Listeria innocua, Staphylococcus aureus). Ocenili smo izoelektrično točko in molekulsko maso bakteriocinskega kompleksa ter njegovih podenot. Bakteriocine smo izolirali iz supernatanta kulture v bujonu MRS s precipitacijo z amonijevim sulfatom, kationsko izmenjevalno kromatografijo, kromatografijo s hidrofobnimi interakcijami in tekočinsko kromatografijo z obrnjenimi fazami FPLC. Ugotovili smo aminokislinsko sestavo dveh izoliranih bakteriocinov in delno zaporedje aminokislin na N-terminalnem delu molekul. Bakteriocini so bili v bujonu MRS v skupkih z Mw, večjo od 150.000, in pI 5,1-5,3, Mw podenot pa je bila 3500-5000. Pri obeh bakteriocinih smo ugotovili visoko zastopanost glicina in alanina. N-terminalni zaporedji aminokislin sta bili zelo malo podobni zaporedjem pri ostalih bakteriocinih. Kaže, da acidocina LF221 A in B sodita v II. skupino bakteriocinov MKB.