Culture-dependent Assays
Culture-dependent Assays - Related Videos
10:14
Biochemical Assays for Analyzing Activities of ATP-dependent Chromatin Remodeling Enzymes
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Cited by 4 •
2014
Here we describe biochemical assays that can be used to characterize ATP-dependent chromatin remodeling enzymes for their abilities to 1) catalyze ATP-dependent nucleosome sliding, 2) engage with nucleosome substrates, and 3) hydrolyze ATP in a nucleosome- or DNA-dependent manner.
04:03
An In Vitro Assay to Measure Antibody-Dependent Cellular Phagocytosis by Phagocytes
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2025
This video demonstrates an assay to measure the antibody-dependent cellular phagocytosis (ADCP) by breast milk phagocytes. Fluorescently labeled microspheres conjugated to an antigen-antibody complex, are combined with a cell suspension isolated from breast milk to induce antibody-dependent cellular phagocytosis by the phagocytic leukocytes. Upon labeling the cells with antibodies against common leukocyte antigen (CD45), flow cytometry is used to measure the fluorescence intensity of...
06:29
Salinity-dependent Toxicity Assay of Silver Nanocolloids Using Medaka Eggs
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Cited by 2 •
2016
Embryonic stages are the most susceptible to xenobiotics. Although chemical toxicity depends on salinity, no method exists to test the salinity dependence of toxicity to aquatic organisms. Here, we describe a new and high-throughput method for determining the salinity dependence of toxicity to aquatic embryos.
05:35
An In Vitro Assay to Examine the Antibody-Dependent Enhancement of Viral Infection
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2025
This video demonstrates an assay to measure antibody-dependent enhancement (ADE) of Dengue virus infection using Zika Virus Convalescent Serum. The assay uses Dengue reporter viral particles (RVPs) encoding a green fluorescent protein. Serum antibodies against the Zika Virus cross-react with RVPs to form a complex. The bound antibodies enhance RVP uptake by cells expressing the Fc receptor, which is detected using flow cytometry.
12:03
Viability Assays for Cells in Culture
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Cited by 39 •
2014
Therapeutic compounds are often first examined in vitro with viability assays. Blind cell counts by a human observer can be highly sensitive to small changes in cell number but do not assess function. Computerized viability assays, as described here, can assess both structure and function in an objective manner.
FAQs
The central interpretive issue is that a positive result reflects organisms able to grow under selected laboratory conditions, not necessarily the full microbial population in the sample. Medium composition, temperature, oxygen availability, and incubation time favor some organisms. Consequently, low recovery can indicate unsuitable conditions rather than true absence.
Medium composition, temperature, oxygen availability, and incubation time directly shape which organisms produce detectable growth. A condition that supports one part of a community may limit another, so changing the assay environment can change both the number of organisms recovered and the types observed. These variables must therefore be defined when interpreting results.
Culture-dependent assays provide evidence about organisms that remain viable and cultivable under the selected conditions, whereas molecular approaches can add information about microbial communities beyond those recovered in culture. Using both approaches helps distinguish growth-based recovery from broader community detection and reveals where laboratory cultivation conditions may have excluded organisms.
Measured colonies or other culture changes can support microbial enumeration and further characterization. A count estimates the recoverable population under the assay conditions, while growth selected for isolation can produce pure cultures for phenotypic identification. The resulting information combines a measurement of growth with observable characteristics useful for comparing microorganisms.
The workflow begins by inoculating a sample onto or into a suitable growth medium. The inoculated material is then incubated at defined temperature, oxygen, and time conditions. After incubation, researchers measure colonies or other culture changes and may analyze the growth further for enumeration, isolation, phenotypic identification, or susceptibility testing.
They are valuable when investigators need information about viable, cultivable microorganisms, including microbial enumeration, pure-culture isolation, phenotypic identification, or antimicrobial susceptibility testing. Applications include clinical samples, food safety, environmental systems, and microbial community analysis. In each setting, results also indicate which organisms can grow under the selected laboratory conditions.