Indicator Host Cells
Indicator Host Cells - Related Videos
02:39
Indicators
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2020
Certain organic substances change color in dilute solution when the hydronium ion concentration reaches a particular value. For example, phenolphthalein is a colorless substance in any aqueous solution with a hydronium ion concentration greater than 5.0 × 10−9 M (pH < 8.3). In more basic solutions where the hydronium ion concentration is less than 5.0 × 10−9 M (pH > 8.3), it is red or pink. Substances such as phenolphthalein, which can be used to determine the pH of a solution, are called...
04:15
Extracting Host Cell Lysate from Infected Host Cells Cultured in a Permeable Membrane System
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2025
This video demonstrates a permeable membrane insert system to investigate the impact of bacterial toxins on host cells in a controlled and isolated manner. This approach allows for the selective exposure of the cells to the toxins while maintaining a physical separation that mimics the natural host-pathogen interaction.
08:17
Water Quality Analysis via Indicator Organisms
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2023
Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba -The University of Arizona Demonstrating Author: Luisa Ikner Water quality analysis monitors anthropogenic influences such as pollutants, nutrients, pathogens, and any other constituent that can impact the water’s integrity as a resource. Fecal contamination contributes microbial pathogens that threaten plant, animal, and human health with disease or illness. Increasing water demands and strict quality standards require that water...
03:05
Detection of Bacterial Adherence to Host Cells Using Fluorescence Imaging
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2025
This video demonstrates the bacterial adherence assay to evaluate GFP-tagged bacterial adherence to epithelial cell culture to study the dynamics of host-pathogen interactions using fluorescence microscopy-based imaging.
03:41
Isolation of Intracellular Pathogenic Bacteria from Infected Host Cells
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2026
Source: Sigal, N., et al. RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells. J. Vis. Exp. (2016).This video demonstrates the isolation of internalized pathogenic bacteria from infected bone marrow-derived macrophages (BMDMs). Bacteria are allowed to attach to host cells, and unattached bacteria are washed away. After internalization, an antibiotic is added to eliminate non-internalized bacteria. The host cells are lysed, centrifuged, and the supernatant is...
FAQs
Compatibility determines whether the agent can enter the selected cells, replicate, and produce a visible response. Cells that do not support the agent may show no detectable change even when the sample contains biological material. This relationship makes host selection important for revealing infectivity, examining host range, and interpreting negative results in culture-based studies.
Replication links the observed cellular response to biological activity rather than simple exposure to a sample. As a compatible agent multiplies, it may cause lysis, cytopathic changes, or plaques that reveal an active infectious process. Consequently, the response can support studies of replication and help distinguish biologically active agents from material that produces no detectable effect.
These outcomes provide different visible readouts of agent-driven damage or localized activity. Lysis indicates destruction of susceptible cells, cytopathic changes show altered cell appearance or behavior, and plaques mark affected areas within a cell or bacterial lawn. Comparing such responses helps researchers detect agents, support isolation, and assess biological activity under culture conditions.
The general workflow is to expose compatible living cells to the test material, maintain them under suitable culture conditions, and examine them for a detectable response. Researchers then use effects such as lysis, cytopathic changes, or plaque formation to support agent detection, isolation, or measurement. The selected cell system must match the biological question and suspected agent.
When an agent affects localized regions in a cell or bacterial lawn, the resulting plaques provide visible evidence of activity in those areas. This pattern can support measurement of infectious material and help researchers isolate an agent for further characterization. The approach is especially useful when a clear spatial response is easier to interpret than generalized culture changes.
These systems are useful for examining pathogen biology, testing environmental samples, and studying how antiviral treatments affect infectious agents. They also support characterization of host range and replication because different selected cells can reveal whether an agent grows in a particular biological context. The resulting responses connect culture observations with questions about infectivity and treatment effects.