Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Positive and Negative Feedback Loops01:18

Positive and Negative Feedback Loops

Animal organs and organ systems constantly adjust to internal and external changes through a process called homeostasis ("steady state"). Examples of these changes include regulation of the level of glucose or calcium in the blood or internal responses to external temperatures. Homeostasis requires  maintaining an internal dynamic equilibrium:
Root Loci for Positive-Feedback Systems01:23

Root Loci for Positive-Feedback Systems

The Hartley oscillator is a positive feedback system that sustains oscillations by feeding the output back to the input in phase, thereby reinforcing the signal. Positive feedback systems can be viewed as negative feedback systems with inverted feedback signals. In these systems, the root locus encompasses all points on the s-plane where the angle of the system transfer function equals 360 degrees.
The construction rules for the root locus in positive feedback systems are similar to those in...
Current Growth And Decay In RL Circuits01:30

Current Growth And Decay In RL Circuits

The current growth and decay in RL circuits can be understood by considering a series RL circuit consisting of a resistor, an inductor, a constant source of emf, and two switches. When the first switch is closed, the circuit is equivalent to a single-loop circuit consisting of a resistor and an inductor connected to a source of emf. In this case, the source of emf produces a current in the circuit. If there were no self-inductance in the circuit, the current would rise immediately to a steady...
Cell Signaling Feedback Loops01:07

Cell Signaling Feedback Loops

Positive and negative feedback loops are crucial for regulating biological signaling systems. These feedback loops are processes that connect output signals to their inputs.
Negative feedback loops
Most signaling systems have negative feedback loops that can perform different functions such as output limiter, and adaptation.
Output limiter
Upon receiving an input signal, the cellular response rapidly increases until a threshold is reached. Beyond this threshold, a negative feedback loop...
Negative and Positive Feedback01:18

Negative and Positive Feedback

Animal organs and organ systems constantly adjust to internal and external changes through a process called homeostasis ("steady state"). Examples of these changes include regulation of the level of glucose or calcium in the blood or internal responses to external temperatures. Homeostasis requires  maintaining an internal dynamic equilibrium:
Effects of feedback01:24

Effects of feedback

Feedback in control systems plays a critical role in shaping various operational parameters, extending beyond simple error reduction to influence stability, bandwidth, gain, impedance, and sensitivity. Understanding these effects requires examining a basic feedback system characterized by defined input, output, error, and feedback signals.
Feedback significantly modifies the gain of a control system. The gain of a system without feedback is altered by a factor of one plus GH, where G represents...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Integrating theory and machine learning to reveal determinants of plasmid copy number.

Nature communications·2026
Same author

Therapeutic Applications of Engineered Cell Death, Arrest, and Persistence.

Annual review of biomedical engineering·2026
Same author

Mapping single-cell responses to population-level dynamics during antibiotic treatment.

Molecular systems biology·2026
Same author

Prototyping Minimal Extracellular Vesicle Mimetics Using Cell-Free Synthesis.

ACS nano·2026
Same author

A foundation model for microbial growth dynamics.

bioRxiv : the preprint server for biology·2026
Same author

Spatial proximity dictates bacterial competition and expansion in microbial communities.

Nature communications·2025

Related Experiment Video

Updated: Jun 19, 2026

Light-Controlled Fermentations for Microbial Chemical and Protein Production
08:37

Light-Controlled Fermentations for Microbial Chemical and Protein Production

Published on: March 22, 2022

Emergent bistability by a growth-modulating positive feedback circuit.

Cheemeng Tan1, Philippe Marguet, Lingchong You

  • 1Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.

Nature Chemical Biology
|October 6, 2009
PubMed
Summary

Synthetic gene circuits can unexpectedly become bistable due to host cell growth changes. Engineering gene circuits requires considering host physiology modulation for predictable synthetic biology applications.

More Related Videos

Reliably Engineering and Controlling Stable Optogenetic Gene Circuits in Mammalian Cells
09:20

Reliably Engineering and Controlling Stable Optogenetic Gene Circuits in Mammalian Cells

Published on: July 6, 2021

A Microfluidics Approach for the Functional Investigation of Signaling Oscillations Governing Somitogenesis
08:06

A Microfluidics Approach for the Functional Investigation of Signaling Oscillations Governing Somitogenesis

Published on: March 19, 2021

Related Experiment Videos

Last Updated: Jun 19, 2026

Light-Controlled Fermentations for Microbial Chemical and Protein Production
08:37

Light-Controlled Fermentations for Microbial Chemical and Protein Production

Published on: March 22, 2022

Reliably Engineering and Controlling Stable Optogenetic Gene Circuits in Mammalian Cells
09:20

Reliably Engineering and Controlling Stable Optogenetic Gene Circuits in Mammalian Cells

Published on: July 6, 2021

A Microfluidics Approach for the Functional Investigation of Signaling Oscillations Governing Somitogenesis
08:06

A Microfluidics Approach for the Functional Investigation of Signaling Oscillations Governing Somitogenesis

Published on: March 19, 2021

Area of Science:

  • Synthetic biology
  • Microbial engineering
  • Systems biology

Background:

  • Synthetic gene circuits are typically designed assuming a stable host cell 'chassis'.
  • However, circuit activation can alter host cell physiology, impacting circuit performance.
  • This interaction between engineered circuits and host cells is crucial for predictable outcomes.

Purpose of the Study:

  • To investigate how host cell physiology modulation affects synthetic gene circuit behavior.
  • To explain the counterintuitive observation of bistable gene expression in a simple self-activating T7 RNA polymerase circuit.
  • To highlight the importance of considering host-circuit interactions in synthetic biology.

Main Methods:

  • Engineering a synthetic gene circuit with mutant T7 RNA polymerase (T7 RNAP*) in Escherichia coli.
  • Analyzing gene expression dynamics and bacterial growth rates.
  • Developing and validating mathematical models that incorporate host physiology effects.

Main Results:

  • The T7 RNAP* circuit exhibited bistable gene expression despite noncooperative activation.
  • Circuit activation led to significant bacterial growth retardation.
  • Nonlinear dilution of T7 RNAP* due to altered growth rates explained the observed bistability.

Conclusions:

  • Host cell growth modulation is a significant factor influencing synthetic gene circuit behavior.
  • A novel mechanism for generating bistability in synthetic circuits via host physiology effects was identified.
  • Accounting for host-circuit interactions is essential for robust synthetic gene circuit design and engineering.