Tryptophan Auxotrophic E. Coli
Tryptophan Auxotrophic E. Coli - Related Videos
12:07
Chemical Modification of the Tryptophan Residue in a Recombinant Ca2+-ATPase N-domain for Studying Tryptophan-ANS FRET
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2021
ANS binds to the Ca2+-ATPase recombinant N-domain. Fluorescence spectra display a FRET-like pattern upon excitation at a wavelength of 295 nm. NBS-mediated chemical modification of Trp quenches the fluorescence of the N-domain, which leads to the absence of energy transfer (FRET) between the Trp residue and ANS.
03:40
Measuring E. coli Bacterial Load in Drosophila melanogaster following E. coli Infection
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In this video, we demonstrate a technique for measuring the E. coli bacterial load after injecting E. coli into the thorax of Drosophila melanogaster.
04:30
Preparation of E. coli Spheroplasts
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2025
Source: Figueroa, D. M., et.al. Production and Visualization of Bacterial Spheroplasts and Protoplasts to Characterize Antimicrobial Peptide Localization. J. Vis. Exp. (2018)This video demonstrates the production of Escherichia coli spheroplasts by first inhibiting cell division to induce filamentation, followed by enzymatic digestion of the cell wall. The process includes controlled addition of a chelating agent, DNase, and an osmotic stabilizer to ensure proper spheroplast formation and...
03:41
Production of Virus-like Particles in Engineered E. coli
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2026
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13:31
Generation of Enterobacter sp. YSU Auxotrophs Using Transposon Mutagenesis
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Cited by 3 •
2014
Enterobacter sp. YSU grows in glucose minimal salts medium. Auxotrophs are generated by transforming it with a transposome which randomly inserts itself into the host genome. Mutants are found by replica plating from complex medium to minimal medium. Interrupted genes are identified by gene rescue and sequencing.
FAQs
A disruption in one part of the tryptophan biosynthetic pathway prevents the cells from completing endogenous tryptophan production. Growth then becomes dependent on either supplying tryptophan externally or restoring the missing pathway function. This creates a direct connection between pathway activity and cellular proliferation, allowing researchers to examine biosynthetic regulation or identify successful genetic complementation.
External tryptophan acts as a controllable input for growth because the cells cannot produce enough of the amino acid through their disrupted pathway. In defined media, researchers can relate growth to tryptophan availability and distinguish conditions that support proliferation from those that do not. This dependence makes nutrient supply a useful variable for studying metabolic behavior.
Genetic complementation restores the missing pathway function in an auxotrophic strain, allowing cells to regain the capacity associated with tryptophan biosynthesis. When growth becomes possible without relying on externally supplied tryptophan, that response links survival or proliferation to restoration of the disrupted genetic function. The system therefore supports selection for constructs that provide the required complementation.
Researchers can cultivate the strain in defined media in which tryptophan availability is deliberately controlled. Comparing growth under supplemented and restricted conditions reveals how strongly proliferation depends on the external amino acid or on restoration of biosynthetic activity. This approach also provides a controlled setting for investigating metabolic regulation without relying on an undefined nutrient source.
Tryptophan-dependent selection is useful when researchers need growth to indicate whether a genetic change has restored the missing biosynthetic function. Cells carrying an effective complementation construct can be distinguished through their ability to grow under conditions where the auxotrophic requirement is not otherwise satisfied. This links a selectable growth outcome to the engineered genetic state.
In recombinant protein production and pathway engineering, tryptophan dependence can connect cell growth or productivity with amino acid availability and biosynthetic activity. Researchers can use that relationship to examine how engineered pathways influence cellular performance or how production conditions affect the system. The strains therefore provide a bioengineering platform where metabolic function is linked to measurable growth or output.