Effect of inductors on bacteriocin activity in Yersinia strains

PASCUAL LOURDES INÉS; ESCUDERO MARÍA ESTHER; MATTAR DOMINGUEZ MARÍA AIDA; FAVIER GABRIELA ISABEL

Congreso; XXIX Reunión Anual de la Sociedad de Biología de Cuyo; 2021

Bacteriocins (BA) are ribosomal peptides with antibacterial activity produced by certain species of the Yersinia genus. Its synthesis and/or secretion can be increased by different inducing agents, which act by different mechanisms on the bacteriocin-producing strains (BPS). These mechanisms are mainly based on obtaining better growth conditions for BPS or in increased secretion and release of the BA from the bacterial cell. In this work, the effect of inducing agents on the production and/or secretion of BA from Yersinia strains was evaluated. Y. enterocolitica B1A and Y. intermedia B1 and B6 strains were tested as bacteriocin-producing strains (BPS), which were cultured with each of the following inducers (IA): Tween 20, Tween 80, cysteine ​​and H202. Three pathogenic Y. enterocolitica strains belonging to B2, B3 and B4 were used as indicator strains (IS) of the antimicrobial effect. The spot technique was performed on a double layer agar. BPS added from each IA (BPS+IA) and IS were cultured in Luria Bertani broth (LB) with shaking at 25°C for 18 h, and inocula were adjusted to a concentration corresponding to an ODʎ610 0.2. From BPS + IA, two-fold dilutions were made in LB, and 10 μl of each one was placed on Petri plates containing semisolid agar previously inoculated with IS. Plates were incubated at 25°C for 18 h. The reciprocal of the highest dilution of BPS+IA that produced total IS inhibition was considered as the titer and expressed in arbitrary units per ml (AU ml -1). For comparison, BPS was used without the addition of IA and results represent the average of three different experiments. This study showed that cysteine ​​added to BPS ​​increased bacteriocin production by Y. intermedia B1 strain on pathogenic Y. enterocolitica B2 and B4, with values ​​of 17.067 + 7.390 AU / ml and 12.800 + 0 AU / ml, respectively, compared to BPS without IA (p < 0.05). Other IA did not show an increase in the production of BA by the remaining strains evaluated. These results could demonstrate that cysteine increases the bacteriocin production, by decreasing the reduction potential necessary and creates a more favorable environment for the growth of facultative anaerobic species, such as Yersinia strains. Our finding suggests that certain IA could increase the production and /or secretion of BA in certain bacterial strains.