Features | Partner Sites | Information | LinkXpress
Sign In
RANDOX LABORATORIES
GLOBETECH PUBLISHING
FOCUS DIAGNOSTICS, INC.

Bacteria-Based Test Strips Can Monitor Blood Glucose

By Labmedica International staff writers
Posted on 26 Jan 2012
Segments of DNA embedded in bacteria can be coded to detect changes in osmolarity resulting from the presence of glucose in a blood sample.

Students at the Missouri University of Science and Technology (MST, Rolla, USA) used a nonvirulent strain of E.coli with designed genes integrated in the bacteria’s DNA, enabling them to sense the presence of glucose in correlation to changes in osmolarity. When glucose is detected, the bacteria emit a yellow glow, and as its concentration rises, so does the light emitted glow brighter. The system might also eventually serve as the basis for a new method to monitor blood glucose levels by replacing the fluorescent gene with one that would make the bacteria change color, based on glucose concentrations.

To make the device, the students used an intermediate biobrick with a ribosome-binding site and the reporter gene (eYFP), which was then coupled to another biobrick that had three binding sites for the transcriptional regulatory protein phosphorylated OmpR. The phosphorlyation of OmpR by EnvZ (an inner membrane protein that senses osmolarity) positively correlated with the osmolarity of the system. When one or two of the binding sites are occupied, RNA polymerase is recruited to begin downstream transcription of eYFP. However, when all three OmpR binding sites are occupied, RNA polymerase cannot bind, the reporter gene can no longer be produced, and the system is inhibited.

As osmolarity increases from very low levels, the fluorescence produced by the system increases, until it reaches a threshold osmolarity level that when crossed causes the fluorescence to decrease as a result of the ensuing inherent down-regulation of the system. The activity of the system can be quantified because the two-component regulatory system of EnvZ and OmpR controls transcription of the eYFP gene, dictating the level of fluorescence.

“All you would have to do is put the DNA inside a bacteria and you've got your test strip,” said Erica Shannon, a senior year student in biological sciences at MST. “In the future, based on further research, an insulin gene could be added to this system for use in insulin pumps, where specific glucose levels trigger insulin production.”

The project was developed the system as part of an annual competition sponsored by the International Genetically Engineered Machine Foundation (iGEM; Boston, MA, USA) held during October 2011, in Indianapolis (IN, USA); the MST iGEM chapter received a silver medal for their effort.

Related Links:

Missouri University of Science and Technology
International Genetically Engineered Machine Foundation




VIRCELL
Sekisui Diagnostics
DiagCor Bioscience
comments powered by Disqus
Life Technologies

Channels

Clinical Chemistry

view channel
Image: The URiSCAN Super Plus reflectance meter (Photo courtesy of YD Diagnostics).

Semiquantitative Urine Dipstick Evaluated for Microalbuminuria Screening

The urine microalbumin test is used as a screening test for the diagnosis of renal complications in diseases, such as diabetic nephropathy, cardiovascular disease, and hypertension. A urine dipstick... Read more

Microbiology

view channel
Image: The adult free-living female Strongyloides stercoralis with a row of eggs within the body of the nematode (Photo courtesy of the CDC - Centers for Disease Control and Prevention).

Rapid Serological Assay Developed for Strongyloidiasis

Several imperfect methods exist for diagnosing strongyloidiasis and stool examination with microscopic identification of larvae considered the gold standard diagnostic procedure, showing good specificity... Read more

Pathology

view channel
Image: The BD Viper LT System for fully automated, integrated molecular testing on a table top analyzer (Photo courtesy of BD Diagnostics).

Modern Methods Accurately Detects Cervical Cancer

The newer Papanicolaou test (Pap tests) and human papilloma virus (HPV) screening more accurately identify precancerous cellular changes that potentially develop into cervical cancer. Compared to a... Read more

Lab Tech.

view channel
Image: RNAscope detects TP63 mRNA expression in human prostate tissue (Photo courtesy of Advanced Cell Diagnostics).

RNA Biomarker Assay Now Manufactured According to Strict ISO Regulatory Criteria

A line of diagnostic kits that measures RNA biomarkers with single-molecule sensitivity is now being manufactured under the stringent requirements of ISO 13485:2003 certification. Advanced Cell Diagnostics, Inc.... Read more

Industry News

view channel

Social Diagnostics Start-Up to Provide Simple, Affordable Tests Worldwide

The Royal Tropical Institute (KIT; Amsterdam, Netherlands) is establishing a nonprofit, social diagnostics company that develops and markets tests for the diagnosis of poverty-related diseases. Infectious diseases have a global impact; they take no account of national borders and influence the stability of societies... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.