LLNL Human single chromosome libraries

We have recently identified bacteriophage contamination in a proportion of some of the LLNL single chromosome cosmid libraries: apparently coliphage T1-related in most if not all cases. The fact that the original archive plates have very similar contamination patterns to our working copies suggests that the problem is likely to have originated elsewhere. Phage T1 contamination can spread rapidly to other E.coli cultures. We have put procedures in place to minimise the chance of transfer of phage contamination to users through shipments from our centre. We believe that as users of LLNL single chromosme cosmid clones you should be aware of the possibility of phage contamination and apply appropriate microbiological practices to ensure that your labs remain contamination free. We have withdrawn badly contaminated sections of the library. All other clones requested will be tested for phage contamination before shipment, and users will be notified of the result. Clones which test negative for phage will be shipped directly. Users will be notified of phage contamination, and must confirm their willingness to accept contaminated clones before shipment. The methodology for testing for phage is available.

Library LL12NC01 (O-I) Chromosome 12 has been found to be heavily contaminated and has been completely withdrawn. Library LL07NC01 (Y) Chromosome 7 has been found to have the last four plates heavily contaminated and these have been withdrawn.