2. Methodology

#### 2.1 Materials

The biological model used in this study was the wild strain (Bristol N2) nematode C. elegans, fed with the bacteria, uracil auxotroph, Escherichia coli OP50 in Luria-Bertani (LB) medium (10 g/L NaCl, 10 g/L tryptone, 5 g/L yeast extract) [27]. Both organisms were obtained through the Department of Chemical and Biological Sciences of Universidad de las Américas Puebla.

#### 2.2 Maintenance and growth conditions

Nematodes were maintained at 22 2°C in nematode growth medium (NGM) plates [3 g/L NaCl, 2.5 g/L peptone, 24 g/L bacteriological agar, 1 mL/L 1 M CaCl2, 1 mL/L 1 M MgSO4∙7H2O, 20 mL/L pH 6.0 phosphate buffer, 1 mL/L cholesterol (0.005 g in 1 mL of ethanol)] supplemented with 200 μL of E. coli OP50. Nematodes were taken from NGM plates and washed with 2 mL of M9 solution (6 g/L Na2HPO4, 3 g/L KH2PO4, 5 g/L NaCl, 0.215 g/L MgSO4∙7H2O). They were centrifuged at 4600 rpm and 4°C for 1 min (centrifuge Z 366 K, HERMLE Labortechnik, Germany). Two washes were performed by removing the supernatant, adding 1 mL of M9 solution, and centrifuging under the same conditions. The supernatant was removed, and the residue was placed in new NGM plates with E. coli OP50. The plates were incubated at 22 2°C [27].
