Fig 1.
Growth curve of the isolates (A) B. megaterium CCT 7729 and (B) B. megaterium CCT 7730.
Legend: MM, MMM, and MMC indicate mineral medium, mineral medium with mesotrione, and mineral medium with Callisto, respectively. The bars represent the standard errors on means.
Fig 2.
Cell viability of B. megaterium isolates CCT 7729 and CCT 7730 after 3 h and 14 h of growth in MM, MMM and MMC media.
Data were analyzed using two-way ANOVA followed by Bonferroni´s correction, *p < 0.05. The bars represent the standard errors on means.
Fig 3.
(A) Quantification of H2O2 levels and (B) MDA in the B. megaterium isolates CCT 7729 and CCT 7730 after 3 h and 14 h periods in the MM, MMM, and MMC media.
Data were analyzed using two-way ANOVA followed by Bonferroni’s correction, *p < 0.05. The bars represent the standard errors on means.
Fig 4.
Characterization of the SOD isoforms in B. megaterium isolates CCT 7729 and CCT 7730.
Fig 5.
SOD-PAGE of samples from B. megaterium isolates CCT 7729 and CCT 7730 after 3 and 14 h of incubation in the control (MM) and treatment (MMM and MMC) media.
Fig 6.
CAT-PAGE of B. megaterium CCT 7729 (a) and B. megaterium CCT 7730 (b) after 3 and 14 h of growth in the control medium (MM) and treatment media (MMM and MMC).
Fig 7.
Infrared spectrum profile of the lipid extract obtained after incubation on MM (Panel 1); MMM (Panel 2) and MMC (Panel 3) of B. megaterium CCT 7729, (A) 3 h, (B) 14 h and B. megaterium CCT 7730, (C) 3 h (D) 14 h (FTIR analysis with scans from 4,000 cm-1 to 400 cm-1).
Bands 1 e 2 correspond to (CH2); 3 to (CH3); 4 to (C = O); 5 to (-C = C); 6 to (CH2); 7 to (CH3); 8 to (C-O) and to 9 (CH).
Fig 8.
Graphical representation of the main results showing the different responses system to herbicides of B. megaterium CCT 7729 and CCT 7730.
These strains were originated from water and soil environments contaminated with Callisto (A), respectively. The response system starts with different lipid saturation levels (B), forming a cascade characterized by different levels of membrane permeability and MDA rates (C), interfering with herbicide entry into the bacterial cells and inducing different antioxidant responses (D). Therefore, different levels of H2O2 between the two strains were created, originating distinct intracellular oxidizing environments (E) for each strain and, therefore, different degradation routes. These response systems interfered with the growth ability (F) and viability rates (G) and may be associated with the nutrient availability of the isolation environments of each strain (A). ↑ Represents significant increase compared with the control and ↓ represents significant decrease compared with the control.