A Facile and Modified Scheme for Synchronization and Isolation of Nematode Eggs

Abstract

Nematodes are common pests that damage agricultural crop plants. Some of them are beneficial while others are parasitic and harmful to plants, animals and humans. Several in vitro studies have aimed to develop chemicals to kill parasitic nematodes, while others have been conducted to use beneficial nematodes as biocontrol agents. However, the preparation of large quantities of nematode eggs in a laboratory setting is challenging. Traditional egg isolation protocols involve the use of sieves to filter eggs or the use of chemicals that can be harmful to nematodes while isolating the eggs. Our method utilizes 1.5 × 1.5 cm sized chunks of bacterial or fungal feed to lure nematodes. A subsequent gentle washing of the consumed chunk with distilled water provides a rapid and straightforward method of collecting eggs in 6-well polystyrene plates and removing unwanted nematodes. Approximately 4000 Bursaphelenchus xylophilus eggs from a fungal chunk and 2400 Caenorhabditis elegans eggs from a bacterial chunk were obtained when tested. This study shows a protocol for the isolation of eggs and synchronization of nematode stages that is relatively straightforward, rapid, eco-friendly, and efficient. The protocol also provides a chemical-free and a reliable, simple means of separating eggs from adults and induces the synchronization of nematodes based on the simple concept that gravid nematodes can be provoked to lay eggs by providing additional feed.