The determination of colony-forming units (CFU) is the gold-standard technique for quantifying bacteria, including Mycobacterium tuberculosis which can take weeks to form visible colonies. Here we describe a micro-CFU for CFU determination with increased time efficiency, reduced lab space and reagent cost, and scalability to medium and high throughput...

Source: Whitney Swanson1,2, Frances V. Sjaastad2,3, and Thomas S. Griffith1,2,3,4
1 Department of Urology, University of Minnesota, Minneapolis, MN 55455
2 Center for Immunology, University of Minnesota, Minneapolis, MN 55455
3 Microbiology, Immunology, and Cancer Biology Graduate Program, University of Minnesota, Minneapolis, MN 55455
4 Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455
Enzyme-linked immunosorbent assay (ELISA) is frequently used to measure the presence...

An enzyme-linked immunosorbent assay (ELISA) is typically performed to detect the presence and/or amount of a target protein of interest within an experimental sample. Detection of the target protein is made possible by antibodies, which make the ELISA an immunoassay. Through a series of incubation and washing steps, these antibodies, which are frequently linked, or conjugated, to an enzyme, will detect protein coating the bottom of a well on a microtiter plate. When exposed to a substrate,...

Here we describe an indirect ELISA sandwich immunocapture to determine the immunogenic glycoprotein contents in rabies vaccines. This test uses a neutralizing Monoclonal Antibody (mAb-D1) recognizing glycoprotein trimers. It is an alternative to the in vivo NIH test to follow the consistency of vaccine potency during production.

After filtration, the precipitate is washed to remove coprecipitated impurities and any remaining mother liquor. Colloidal precipitates, such as silver chloride, are washed with an electrolyte (such as dilute nitric acid) to prevent the peptization of the precipitate. In the case of slightly soluble precipitates, the wash solution contains a common ion to reduce solubility. Lead sulfate, which is slightly soluble in water, is washed with dilute sulfuric acid. Similarly, wash solutions may be...

Every measurement provides three kinds of information: the size or magnitude of the measurement (a number), a standard of comparison for the measurement (a unit), and an indication of the uncertainty of the measurement. While the number and unit are explicitly represented when a quantity is written, the uncertainty is an aspect of the errors in the measurement results.