[52] – Storage of Unamplified Phage Libraries on Nylon Filters

Publisher Summary The construction and screening of libraries made using bacteriophage λ vectors is an essential step in the analysis of the structure and function of genes and gene regions. The advantage of library amplification is that an unlimited supply of the library is generated that is stable for years. The disadvantage is that the complexity of the library is altered due to variations in the growth rates of different recombinant phages such that some clones become overrepresented and some clones become underrepresented or even lost. In case of the former, this means that repeat isolates of the same clone will be characterized while in case of the latter, several library equivalents will have to be screened if a positive phage is to be detected. Therefore, the most efficient way to obtain clones from a λ library is to screen the unamplified library directly. The method does require the storage and handling of plates of frozen agar. Instead, the phages are stored on nylon filters. This makes storage and handling easier and makes it possible to prepare both an unamplified and amplified version of the same library.