PANTHER sensor from MIT Lincoln Laboratory quickly detects pathogens

This prototype of the PANTHER device is about one cubic foot and weighs 37 pounds.

Researchers at MIT Lincoln Laboratory have developed a powerful sensor that can detect airborne pathogens such as anthrax and smallpox in less than three minutes.

The new device, called PANTHER (for PAthogen Notification for THreatening Environmental Releases), represents a "significant advance" over any other sensor, said James Harper of Lincoln Lab's Biosensor and Molecular Technologies Group. Current sensors take at least 20 minutes to detect harmful bacteria or viruses in the air, but the PANTHER sensors can do detection and identification in less than 3 minutes.

The technology has been licensed to Innovative Biosensors, Inc. (IBI) of Rockville, Md. In January, IBI began selling a product, BioFlash, that uses the PANTHER technology.

"There is a real need to detect a pathogen in less than three minutes, so you have time to take action before it is too late," said Harper, the lead scientist developing the sensor.

The PANTHER sensor uses a cell-based sensor technology known as CANARY (after the birds sent into mines to detect dangerous gases), and can pick up a positive reading with only a few dozen particles per liter of air.

The device could be used in buildings, subways and other public areas, and can currently detect 24 pathogens, including anthrax, plague, smallpox, tularemia and E. coli.

"There's really nothing out there that compares with this," said Todd Rider of Lincoln Lab's Biosensor and Molecular Technologies Group, who invented the CANARY sensor technology.

Rider started developing CANARY in 1997 when he realized that there were no sensors available that could rapidly detect pathogens. His idea was to take advantage of nature's own defense system--specifically the B cells that target pathogens in the human body. "B cells in the body are very fast and very sensitive," Rider said.

The CANARY concept uses an array of B cells, each specific to a particular bacterium or virus. The cells are engineered to emit photons of light when they detect their target pathogen. The device then displays a list of any pathogens found.

CANARY is the only sensor that makes use of immune cells. Other available sensors are based on immunoassays or PCR (polymerase chain reaction), which take much longer and/or are not as sensitive as CANARY.

Rider and colleagues first reported the success of CANARY (which stands for Cellular Analysis and Notification of Antigen Risks and Yields) in the journal Science in 2003. Since then, they have been working to incorporate the technology into a portable device that could be used in a variety of settings where environmental threats might exist.

The new device, PANTHER, takes the CANARY technology and combines it with an air sampler that brings pathogens into contact with the detector cells. The prototype sensor is about a cubic foot and weighs 37 pounds and is well suited to building-protection applications. With minor modifications it could also enhance biological detection capabilities for emergency responders.

CANARY has been tested in rural and coastal environments as well as urban ones. It could eventually be used on farms or in food-processing plants to test for contamination by E. coli, salmonella, or other food-borne pathogens.

Another potential application is in medical diagnostics, where the technology could be used to test patient samples, giving rapid results without having to send samples to a laboratory.

"Instead of going to the doctor's office and waiting a few days for your test results, with CANARY you could get the results in just a minute or so," said Rider.

The research on PANTHER was funded by the Defense Threat Reduction Agency.

Human Cytomegalovirus-encoded microRNA regulates expression of multiple genes involved in replication

Our ability to understand the biology of viruses depends not only on functional analysis of genes they encode but also on specific regulation of those genes during viral infection. In herpesviruses, virus gene regulation is highly complex and plays a significant role in determining the virus replication cycle during acute, latent, or persistent infection. The discovery that many herpesviruses express small regulatory RNAs, known as microRNAs (miRNAs), has opened up a whole new area of research in regulation of gene expression. A recent paper demonstrates that a microRNA expressed by human cytomegalovirus is able to regulate multiple virus genes, including one gene thought to be crucial for both acute and latent stages of viral infection in the host. Expression of this microRNA results in a significant reduction in viral replication. This work therefore demonstrates that viral microRNAs can regulate multiple viral genes and can have significant effects on the replication of a virus.

Although multiple studies have documented the expression of over 70 novel virus-encoded microRNAs (miRNAs), the targets and functions of most of these regulatory RNA species are unknown. In this study a comparative bioinformatics approach was employed to identify potential human cytomegalovirus (HCMV) mRNA targets of the virus-encoded miRNA miR-UL112-1. Bioinformatics analysis of the known HCMV mRNA 3′ untranslated regions (UTRs) revealed 14 potential viral transcripts that were predicted to contain functional target sites for miR-UL112-1. The potential target sites were screened using luciferase reporters that contain the HCMV 3′UTRs in co-transfection assays with miR-UL112-1. Three of the 14 HCMV miRNA targets were validated, including the major immediate early gene encoding IE72 (UL123, IE1), UL112/113, and UL120/121. Further analysis of IE72 regulation by miR-UL112-1 with clones encoding the complete major immediate early region revealed that the IE72 3′UTR target site is necessary and sufficient to direct miR-UL112-1-specific inhibition of expression in transfected cells. In addition, miR-UL112-1 regulation is mediated through translational inhibition rather than RNA degradation. Premature expression of miR-UL112-1 during HCMV infection resulted in a significant decrease in genomic viral DNA levels, suggesting a functional role for miR-UL112-1 in regulating the expression of genes involved in viral replication. This study demonstrates the ability of a viral miRNA to regulate multiple viral genes