Gram Negative Bacteria
Gram Negative Bacteria - Related Videos
04:02
Generation of Spheroplasts from Gram-Negative Bacteria
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2026
Source: Figueroa, D. et. al. Production and Visualization of Bacterial Spheroplasts and Protoplasts to Characterize Antimicrobial Peptide Localization. J. Vis. Exp. (2018).This video demonstrates the preparation of spheroplasts from rod-shaped, gram-negative bacteria. Bacteria are grown in the presence of an antibiotic to form elongated filaments. These are washed with a hypertonic solution and treated with a lysis buffer to remove the outer cell wall. Hypotonic treatment forms spheroplasts,...
02:52
Isolation of Gram-Negative Bacteria with Genomic Transposon Insertions
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2025
Source: Kazi, M. I., et. al., Generating Transposon Insertion Libraries in Gram-Negative Bacteria for High-Throughput Sequencing. J. Vis. Exp. (2020)This video demonstrates the selection, quantification, and preservation of Gram-negative recipient bacteria carrying transposon insertions based on kanamycin resistance.
02:35
Aptamer-Assisted Acoustophoresis for Microfluidic Separation of Gram-Negative Bacteria
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2025
Source: Choi, H. J., et al. Microfluidic Acoustophoresis for Flowthrough Separation of Gram-Negative Bacteria using Aptamer Affinity Beads. J. Vis. Exp. (2022)This video demonstrates the method of selectively separating Gram-negative bacteria from a mixed bacterial sample using aptamer-coated microbeads and acoustic forces within a microfluidic chip.
12:57
Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria
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Cited by 67 •
2013
Isolation and characterization of the lipid A domain of lipopolysaccharide (LPS) from gram-negative bacteria provides insight into cell surface based mechanisms of antibiotic resistance, bacterial survival and fitness, and how chemically diverse lipid A molecular species differentially modulate host innate immune responses.
03:47
Separation of Inner and Outer Membrane Fractions of Gram-Negative Bacteria
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2025
Source: Cian, M. B. et. al., Separation of the Cell Envelope for Gram-negative Bacteria into Inner and Outer Membrane Fractions with Technical Adjustments for Acinetobacter baumannii. J. Vis. Exp. (2020)This video demonstrates the separation of the inner and outer membrane fractions of Gram-negative bacteria using sucrose gradient ultracentrifugation. The membrane fractions are purified and stored at low temperatures for targeted analysis of membrane-specific components.
FAQs
The outer membrane is a functional interface rather than only an outer boundary. Its lipopolysaccharide content is part of the envelope associated with nutrient transport, interactions with hosts, and susceptibility to antibiotics and detergents. Consequently, studying this membrane helps biologists connect Gram-negative cell structure with how these microorganisms encounter their surroundings and contribute to disease-related processes.
During Gram staining, alcohol removes the crystal violet–iodine complex from these cells. The counterstain can then color them pink or red, so the observed result depends on the sequence of primary staining, iodine treatment, alcohol exposure, and counterstaining. This mechanism links a visible laboratory result to the distinctive organization of the cell envelope.
The envelope determines how Gram-negative bacteria interact with substances in their surroundings, including antibiotics and detergents. Its inner membrane, thin peptidoglycan layer, and outer membrane create the structural context in which susceptibility is studied. This relationship makes envelope biology important when researchers interpret treatment effects or investigate why microorganisms respond differently to antimicrobial conditions.
The arrangement of an inner membrane, a thin peptidoglycan layer, and an outer membrane provides a framework for interpreting Gram-negative biology. Peptidoglycan occupies the space between the membranes, while the outer membrane contains lipopolysaccharide. Examining these components together helps relate envelope architecture to nutrient transport, host interactions, and susceptibility to antibiotics and detergents.
A basic Gram-staining workflow applies crystal violet, uses iodine to form the crystal violet–iodine complex, exposes the cells to alcohol, and then applies a counterstain. Alcohol removes the primary-stain complex from Gram-negative cells, allowing the counterstain to produce a pink or red appearance. The final color provides a visible classification result for microbiological study.
Researchers examine Gram-negative bacteria across clinical microbiology, environmental biology, biotechnology, and antimicrobial-resistance studies. In clinical settings, the envelope supports investigations of disease and treatment. Environmental and biotechnology research considers how these microorganisms interact with their surroundings or support biological applications, while resistance studies focus on susceptibility to antimicrobial interventions.
Gram-negative classification connects a staining result with envelope features that influence susceptibility to antibiotics and detergents. That connection gives researchers a structural context for interpreting antimicrobial responses rather than treating the color alone as the complete result. In biology, this supports studies of antimicrobial resistance alongside broader investigations of microbial structure, disease, and treatment.