Uses of this assay include the rapid enumeration of bacteria in a sample for direct quantification and spiking purposes and determining growth (or inhibition of growth) of bacteria in antimicrobials
Acolyte Biomedica reports successful development of its first life sciences research assay based on adenylate kinase (AK) technology.
BacLite Rapitect GN is designed for the rapid and highly sensitive enumeration of gram-negative bacterial cells.
Performance data compares extremely favourably with current methods of enumeration, including ATP bioluminescence, says the company.
The time to result is determined by assay design; typical enumeration results can be achieved in minutes, and growth based results within a few hours, it says.
Identified uses of the assay include the rapid enumeration of bacteria in a sample for direct quantification and spiking purposes, determining growth (or inhibition of growth) of bacteria in antimicrobials, evaluating the burden of genetic manipulation on organism viability, optimising conditions for bacterial growth, determining growth (or inhibition of growth) in selective culture media, and optimisation of growth conditions for cellular metabolite production.
The BacLite Rapitect GN uses AK as a highly sensitive marker to detect bacterial cell numbers.
Unlike ATP, AK is present at constant levels in all bacteria, irrespective of the organism's metabolic state, and can be used to detect bacteria at much lower levels due to the ADP-ATP amplification process.
The rapid AK assay is up to 100 times more sensitive than standard ATP bioluminescence and up to one million times more sensitive than optical measurements (colorimetric, turbidometric), says Acolyte.
The assay is based on generic gram-negative bacterial lysis and AK mediated bioluminescence.
The bacteria in a sample are non-selectively lysed, releasing the AK from the bacteria into the sample matrix.
An excess of highly purified ADP is added to the sample and the AK catalyses the conversion of the ADP to ATP.
Thermostable firefly luciferase and luciferin is added to the sample and light is emitted in the presence of the ATP.
This is carried out in the presence of the reaction co-factor.
The photon emission is measured using a luminometer to provide a reading quoted in terms of relative light units (RLU).
Marc Green, who managed the development at Acolyte, said: "Users can incorporate any commercially available nutrient media and solutions typically used in microbiology, or use bespoke sample matrixes.
"The assay enables users to add substances to standard nutrient media, such as antimicrobial agents or growth supplements.
"We intend to further develop the Rapitect name through the development of research assays for all prokaryotic and eukaryotic cells".
The gram-negative assay is currently undergoing external evaluation at a major life sciences institute and will be available from the end of July 2005.
