One advantage of the Livermore array is that it provides researchers with the capability of detecting pathogens over the entire range of known viruses and bacteria. Current multiplex polymerase chain reaction (PCR) techniques can at most offer detection from among 50 organisms in one test.
In April, in a Journal of Virology article, Livermore researchers working with a scientist from the San Francisco-based Blood Systems Research Institute said they used the LLMDA technology to confirm the presence of an apparently benign pig virus in a vaccine.
The pig virus, porcine circovirus-1 (PCV-1), was unexpectedly found in GlaxSmithKline's Rotarix vaccine, which is used to prevent diarrhea in babies.
"One result of this research is that it demonstrates how modern technologies could change and drastically improve product safety," Slezak said.
While product safety rules require demonstrating that a list of known contaminants is not present, Slezak said the use of modern advances in DNA sequencing and arrays would allow manufacturers to identify the potential presence of contaminating biological material present in quantities large enough to be of potential concern.
"For each bacteria or virus that has been sequenced anywhere in the world, we have several dozen squares on the checkerboard that will identify sequences from that organism," Slezak explained.
Currently, Slezak's team is testing a next-generation LLMDA that boasts 2.1 million probes. This version contains probes representing about 178,000 viral sequences from some 5,700 viruses, and about 785,000 bacterial sequences from thousands of bacteria.
The latest LLMDA version also encompasses fungi and protozoa - with probes representing about 237,000 fungal sequences
|Contact: Steve Wampler|
DOE/Lawrence Livermore National Laboratory