Technique for en-masse cryo-fixation and processing of second-stage juveniles of Meloidogyne incognita for scanning electron microscopy

Abstract

Large number of second-stage juveniles of root-knot nematode, Meloidogyne incognita was prepared for scanning electron microscopy over a millipore filter (pore size 0.45 µm). The J2 juveniles were quickly immobilized and killed before fixation using the cryo-fixation technique followed by the primary fixation in 2.5% glutaraldehyde pre-cooled at 4-8°C and then secondary vapor fixation in 1% osmium tetraoxide and drying with the series of ethanol without subsequent critical point drying. The specimens were vacuum dried in a desiccator for a period of 24-48 h. Cryo-fixation emphasizes the need to quickly stop cellular activity and thus prevent any surface artifacts that occur due to conventional fixation techniques.

Keywords: Scanning electron microscopy, cryo-fixation, root-knot nematode, Meloidogyne incognita, surface morphology

African Journal of Biotechnology, Vol 13(31) 3689-3691