Comparative analysis of the effect of Ca and Mg ions on antibacterial activity of lactic acid bacteria isolates and their associations depending on cultivation conditions

Abstract

The effects of divalent cations of Ca and Mg on antibacterial activity of lactic acid bacteria (LAB) isolates, as well as their different associations were studied. Most LAB strains and associations revealed significant inhibitory effects in MRS against Gram-positive and Gram-negative test-organisms at different Ca 2+ and Mg 2+ concentrations (determined specifically for each LAB strain and each association). Some LAB strains and communities inhibited the growth of pathogenic test-organisms depending on both ions concentrations and cultivation conditions. Interestingly, the presence of Mg ions in medium significantly decreased the antimicrobial activity of LAB communities against pathogenic test-organisms; on the other hand, the combined mixture of ions essentially increased the inhibitory effect in case of time-spaced cultivation. In contrast, the inhibitory effects of many associations were significantly increased at the presence of Mg 2+ and especially ions combination in case of simultaneous cultivation. The addition of ions combination didn’t affect antibacterial activity of LAB isolates. The results allow us to conclude that Ca and Mg ions had inducible effects on antibacterial activity in case of simultaneous cultivation. This probably can be prospective for creation of new antimicrobial preparations and their possible application.

Antifungal and antibacterial effects of newly created lactic acid bacteria associations depending on cultivation media and duration of cultivation

“…All associations were created in accordance with the method explained by Matevosyan et al [20]. The LAB strains were cultivated in modified MRS broth (10 g l − 1 meat extract, 10 g L − 1 poly-peptone, 5 g L − 1 yeast extract, 20 g L − 1 glucose, 2 g L − 1 ammonium citrate, 0.2 g L − 1 MgSO 4 , 0.05 g L − 1 MnSO 4 , 1 g L − 1 Tween 80, 0.8% agar, sterilization at 1 atm., 15 min) at 37 °C during 24 h. For the same purpose, the 10% milk was used (the milk powder was produced by “Katnarat” LLC, Armenia) [21].…”

“…To determine the antifungal activity, the six most active LAB strains were selected, and from these strains 15 different combinations were created according to Bazukyan et al [19] and Matevosyan et al [20]. The antifungal activity of E. durans was not studied, since it is the reference strain from INRA (Nantes, France), the antifungal activity of which was shown by Ahmadova et al [22].…”

“…The antibacterial activity of 21 different LAB associations was determined. Antibacterial properties of LAB mixed cultures were studied both in modified MRS-broth and milk by two methods of cultivation (simultaneous cultivation of LAB strains and cultivation of these strains separated by time at 37 °C) by agar well diffusion method [20, 23]. Different Gram-positive and Gram-negative representatives of various genera were used for detection of antibacterial activity: Staphylococcus aureus MDC 5233 (MDC, Armenia), Bacillus mesentericus WT, B. subtilis WT-A1 (isolated from a soil sample) and Micrococcus luteus WT (isolated from an air sample), Escherichia coli VKPM-M17 (Russian National Collection of Industrial Microorganisms, Institute of Genetics and Selection of Industrial Microorganisms, Moscow, Russia), Salmonella typhimurium MDC 1759 and Pseudomonas aeruginosa WT272786 (isolated from clinical material and provided by “Prom-Test” LLC, Yerevan, Armenia).…”

Antimicrobial Peptides and Copper(II) Ions: Novel Therapeutic Opportunities

“…While there is no strong evidence of metal binding to bacteriocins, particularly those that contain the ATCUN motif, a recent study shows that the presence of Ca 2+ and Mg 2+ ions in the culture medium induce antimicrobial activities in some LA bacterial strains . There were a variety of suggestions made on how these ions were able to induce activity.…”

“…There were a variety of suggestions made on how these ions were able to induce activity. Proteolytic activity in some LA bacterial strains is increased in the presence of Ca 2+ , suggesting that there may be antimicrobial components produced after proteolysis, some of which may be AMPs. However, the study did not mention the possibility that metal ions binding to the bacteriocins produced by these LA bacterial strains could potentially explain the antimicrobial activity.…”