Bacterial Culture Plating
Bacterial Culture Plating - Related Videos
09:03
Pure Cultures and Streak Plating: Isolation of Single Bacterial Colonies from a Mixed Sample
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2023
Source: Tilde Andersson1, Rolf Lood1 1 Department of Clinical Sciences Lund, Division of Infection Medicine, Biomedical Center, Lund University, 221 00 Lund, Sweden Seemingly impossible to determine, microbial biodiversity is truly astounding with an estimated one trillion coexisting species (1,2). Although particularly harsh climates, like the acidic environment of the human stomach (3) or the subglacial lakes of Antarctica (4), may be dominated by a specific species, bacteria are typically...
03:38
Preparation of a Microfluidic Plate with Bacterial Cells
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2025
Source: Sutlief, A. L., et al. Live Cell Analysis of Shear Stress on Pseudomonas aeruginosa Using an Automated Higher-Throughput Microfluidic System. J. Vis. Exp. (2019).This video demonstrates the preparation of a microfluidic plate for shear stress studies in bacterial cultures. After priming the channels with media, bacterial cells are introduced into the experimental channel and incubated for attachment. Residual media and culture are removed to prepare the system for subsequent shear...
02:08
Assessing Bacterial Swarming Using a Gradient Inhibitor Plate
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2025
Source: Guo, S., et al. Quantifying Bacterial Surface Swarming Motility on Inducer Gradient Plates. J. Vis. Exp. (2022).This video demonstrates the use of a double-layer gradient swarm plate to study bacterial swarming behavior under varying inhibitor concentrations. A plate with a gradient-forming inhibitor in the bottom layer is inoculated with bacteria and incubated. Images are captured at regular intervals to analyze the effect of inhibitor concentration on bacterial swarming.
05:10
A Spot Plate Assay for Evaluating Oxidative Stress Responses in Bacterial Strains
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2025
This video demonstrates a spot plate assay tailored to assess the oxidative stress responses of bacterial strains. Some strains produce pyomelanin, an antioxidant pigment. Conversely, strains treated with a test agent, leading to reduced pyomelanin production, exhibit increased susceptibility to oxidative stress, resulting in decreased cell viability compared to pyomelanin-producing strains.
03:09
A Technique to Prepare a Monoclonal Bacterial Culture
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2025
Source: Lin, P., et al. Synthesizing Sodium Tungstate and Sodium Molybdate Microcapsules via Bacterial Mineral Excretion. J. Vis. Exp. (2018).This video demonstrates the preparation of a monoclonal bacterial culture for mineral production through serial dilution and colony isolation on an agar plate. By shaking the plate with glass beads, individual cells are spatially separated to form genetically uniform colonies, which are then transferred to liquid media for growth. The culture with the...
FAQs
Streaking or spreading distributes cells across the agar surface so that some become physically separated from one another. During incubation, separated cells can multiply into distinct visible colonies rather than remaining mixed in one dense mass. This arrangement makes it easier to examine individual populations and select colony material for identification, characterization, or additional experimentation.
Dilution reduces the number of cells deposited in a given area, increasing the chance that resulting colonies can be distinguished and counted. The number of visible colonies can then support an estimate of viable cell concentration in the original sample. This measurement reflects cells capable of producing colonies under the selected growth and incubation conditions.
Bacterial growth depends on using suitable solid nutrient media and incubation conditions. If those conditions do not support the organisms present, fewer colonies may appear even when viable cells were in the sample. Consequently, colony counts and observed diversity describe growth under the selected conditions, rather than necessarily representing every organism or population in the original material.
A sample is first diluted when necessary, then applied to the surface of solid nutrient agar by streaking or spreading. The plate is incubated under conditions suitable for bacterial growth until visible colonies develop. Researchers can then inspect the separated colonies, count them when appropriate, or use selected colony material for identification and further study.
Researchers can apply this technique when they need to detect bacteria, separate populations, or investigate changes in microbial growth. It supports work with biological and environmental samples, including assessments of microbial diversity, contamination, antibiotic responses, and viable cell concentration. Comparing colony appearance or counts across samples can reveal differences in the populations that grow under the tested conditions.
A separated colony can provide material for further identification, characterization, or experimentation because it may represent a clonal bacterial population derived from a single cell. Researchers can therefore connect later observations to a more defined population than the original mixed sample. Plating also enables comparisons of growth or antibiotic responses among populations recovered from different samples or conditions.