Purification and partial chemical characterization of the antimicrobial peptide cerein 8A.
OBJECTIVE
To purify and to characterize the antimicrobial compound cerein 8A.


RESULTS
Cerein 8A was isolated by ammonium sulfate precipitation, 1-butanol extraction and ion-exchange chromatography. Direct activity on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was observed. The purified substance corresponded to a 26 kDa peptide band. The native protein eluted at the void volume of Sephadex G-100, but within the included volume when a 1.5 mol l(-1) NaCl buffer was used, indicating that cerein 8A aggregates extracellularly. The antimicrobial activity was lost by treatment with proteases and heat. The ultraviolet spectrum was typical of a polypeptide and the infrared spectrum indicates that the peptide contains acyl group(s) in its structure. Intact Bacillus cereus spores were sensitive to cerein 8A at 1600 AU ml(-1).


CONCLUSIONS
Cerein 8A show distinct properties from other antimicrobial peptides of B. cereus, and has a significant inhibitory effect on spores.


CONCLUSIONS
The characterization of a substance active against important pathogens addresses an important aspect of food safety.
Bizani
D
D
Laboratório de Bioquímica e Microbiologia Aplicada, Departamento de Ciência de Alimentos, ICTA, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Dominguez
A P M
AP
Brandelli
A
A
D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D001409:Bacillus cereus / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D001430:Bacteriocins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D013170:Spores / Q000187:drug effects
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001430:Bacteriocins