Transposon insertion sequencing (TIS) is an emerging technique which utilizes a massive transposon mutant library to screen specific phenotype and determine the conditional essential genetic requirements for bacterial fitness under distinct conditions combined with high-throughput parallel sequencing technology. Compared with a massive mutant library in traditional TIS, the defined mutant library sequencing (DML-Seq) has advantages as: 1) efficient mutagenesis; 2) low bottleneck effects; 3) avoid hotpots caused by screening; 4) can be directly used in the following experiments. Here, we described an optimized procedure of DML-Seq for fitness screen to supply classical TIS using the marine pathogenic bacterium Edwardsiella piscicida as an example.

Sphingolipids are major structural components of endomembranes and have also been described as an intracellular second messenger involved in various biological functions in all eukaryotes and a few prokaryotes. Ceramides (Cer), the central molecules of sphingolipids, have been depicted in cell growth arrest, cell differentiation, and apoptosis. With the development of lipidomics, the identification of ceramides has been analyzed in many species, mostly in model insects. However, there is still a lack of research in non-model organisms. Here we describe a relatively simple and sensitive method for the extraction, identification, and quantification of ceramides in Hemiptera Insects (brown planthooper), followed by Ultra-Performance Liquid Chromatography coupled to tandem mass spectrometry

Insects rely on the simple but effective innate immune system to combat infection. Cellular and humoral responses are interconnected and synergistic in insects’ innate immune system. Phagocytosis is one major cellular response. It is difficult to collect clean hemolymph from the small insect like pea aphid. Here, we provide a practicable method for small insects hemocyte phagocytosis assay by taking pea aphid as an example. Furthermore, we provide the protocols for pea aphid rearing and bacterial infection, which offer referential method for related research.