e. for PRI-724 a 1 log-increase of the total cell count). 2The same letter code as for band designation in Figure 3 was used. Figure 3 Population dynamics of cheese surface consortia by TTGE. TTGE analysis was carried out after total DNA extraction of cheese surfaces treated with complex surface consortium F, complex surface consortium M, or defined commercial culture OMK 704 (control cheese). Cheeses were sampled after 1, 7, 14, 21, 37 and 81 days. Each sample was analyzed
on two different gels (high and low GC). Single bands were assigned to species using the database of 15 cultivable species completed by the database of 5 species identified by excision, cloning and sequencing. b, c, C. variabile; d, Mc. gubbeenense; f, uncultured bacterium from marine sediment; h, j, v, C. casei; k, Br. tyrofermentans; l, Brachybacterium sp. or Arthrobacter arilaitensis; m, Br. paraconglomeratum; a, e, g, h, i, n, o, B. linens; p, St. vitulinus; q, St. equorum, St. epidermidis or F. tabacinasalis; q, t, St. equorum; r, E. malodoratus; MRT67307 in vivo w, M. psychrotolerans or Lc. lactis; x, Ag. casei; y, Al. kapii; z’, M. psychrotolerans.
L, Ladder: A, Lb. plantarum SM71; B, Lc. lactis diacetylactis UL719; C, C. variabile FAM17291; E, A. arilaitensis FAM17250; D, F, B. linens FAM17309. Population dynamics of the defined commercial culture OMK 704 by TTGE fingerprinting Population dynamics of the defined commercial culture OMK 704 at species level was assessed by TTGE fingerprinting of total DNA extracts (Figure 3, Table 3). All three species of the culture OMK 704 (C. variabile, A. arilaitensis and B. linens) established themselves on cheese surface during the first 14 days. Each of the five B. linens strains of the culture OMK 704 exhibited a distinguishable strain-specific TTGE SPTBN5 profile (data not shown). The profile of B. linens FAM17309 (Bands
e, o; Figure 3) was detected in the TTGE fingerprint of day 81 cheese, showing that this strain predominated over other B. linens strains at the end of ripening. Additional species not deliberately applied on the cheese colonized the cheese surface along ripening. Two staphylococci species (St. vitulinus; St. equorum) appeared on day 14 as well as M. psychrotolerans and Al. kapii on day 37. Br. tyrofermentans and an uncultured bacterium from marine sediment completed the high GC community at day 81. Repetition of the treatment revealed the same trends regarding the three defined species. However, the development of non-deliberately applied species was different in the repetition. Three additional species colonized the cheese, i.e. Enterococcus sp., C. casei, Ag. casei, while Br. tyrofermentans could not be detected (data not shown).