In this paper we introduce a mathematical model for the tryptophan operon regulatory pathway in Bacillus subtilis. This model considers the transcription-attenuation, and the enzyme-inhibition regulatory mechanisms. Special attention is paid to the estimation of all the model parameters from reported experimental data. With the aid of this model we investigate, from a mathematical-modeling point of view, whether the existing multiplicity of regulatory feedback loops is advantageous in some sense, regarding the dynamic response and the biochemical noise in the system. The tryptophan operon dynamic behavior is studied by means of deterministic numeric simulations, while the biochemical noise is analyzed with the aid of stochastic simulations. The model feasibility is tested comparing its stochastic and deterministic results with experimental reports. Our results for the wildtype and for a couple of mutant bacterial strains suggest that the enzyme-inhibition feedback loop, dynamically accelerates the operon response, and plays a major role in the reduction of biochemical noise. Also, the transcription-attenuation feedback loop makes the trp operon sensitive to changes in the endogenous tryptophan level, and increases the amplitude of the biochemical noise.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jtbi.2012.06.014 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Concentration vs. Optical Density of ESKAPEE Bacteria: A Method to Determine the Optimum Measurement Wavelength.
Sensors (Basel)
December 2024
Institut FEMTO-ST, Université de Franche-Comté, CNRS, F-25000 Besançon, France.
Optical density measurement has been used for decades to determine the microorganism concentration and more rarely for mammalian cells. Although this measurement can be carried out at any wavelength, studies report a limited number of measurement wavelengths, mainly around 600 nm, and no consensus seems to be emerging to propose an objective method for determining the optimum measurement wavelength for each microorganism. In this article, we propose a method for analyzing the absorbance spectra of ESKAPEE bacteria and determining the optimum measurement wavelength for each of them.
View Article and Find Full Text PDFReal-time monitoring of small changes in powder blends and ejected tablets in a low-dose formulation with 1 %w/w of active pharmaceutical ingredient using Raman and near-infrared spatially resolved spectroscopy within a tablet press.
Int J Pharm
January 2025
Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, NJ, 08854, USA; Center for Structured Organic Particulate Systems (C-SOPS), Cranbury, NJ, 08512, USA.
This study used Raman and near-infrared (NIR) spectroscopy to monitor small real-time changes in powder blends and tablets in low-dose pharmaceutical formulations. The research aims to enhance process analytical technology (PAT) in pharmaceutical manufacturing, ensuring high-quality and uniform products with applications to produce drugs with narrow therapeutic indices (NTI). The study utilizes Raman and NIR spatially resolved spectroscopy (SRS) techniques to monitor a moderate cohesive material's active pharmaceutical ingredient (API) concentrations during manufacturing.
View Article and Find Full Text PDFTracking Somatic Mutations for Lineage Reconstruction.
Methods Mol Biol
January 2025
Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel.
The human genome is composed of distinct genomic regions that are susceptible to various types of somatic mutations. Among these, Short Tandem Repeats (STRs) stand out as the most mutable genetic elements. STRs are short repetitive polymorphic sequences, predominantly situated within noncoding sectors of the genome.
View Article and Find Full Text PDFHigh Detection Rates for Prostate-specific Membrane Antigen-avid Prostate Cancer Recurrence at Low Prostate-specific Antigen levels on Extended Axial Field-of-view Positron Emission Tomography/Computed Tomography.
Eur Urol Open Sci
January 2025
Melbourne Theranostic Innovation Centre, Melbourne, Australia.
Background And Objective: Although prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has impacted the investigation and management of biochemical recurrence (BCR) of prostate cancer, negative scans are common at low rising prostate-specific antigen (PSA) levels. PET/CT devices with an extended axial field-of-view, such as the Siemens Biograph Vision Quadra (Quadra) scanner, have substantially higher sensitivity than conventional field-of-view scanners. Our aim was to assess whether the enhanced signal-to-noise ratios achieved on the Quadra scanner improve detection of low-volume disease and thereby increase detection of PC at low PSA levels.
View Article and Find Full Text PDFIn Vivo Neurodynamics Mapping via High-Speed Two-Photon Fluorescence Lifetime Volumetric Projection Microscopy.
Adv Sci (Weinh)
December 2024
State Key Laboratory of Radio Frequency Heterogeneous Integration & Key Laboratory of Optoelectronic Devices and Systems, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Monitoring the morphological and biochemical information of neurons and glial cells at high temporal resolution in three-dimensional (3D) volumes of in vivo is pivotal for understanding their structure and function, and quantifying the brain microenvironment. Conventional two-photon fluorescence lifetime volumetric imaging speed faces the acquisition speed challenges of slow serial focal tomographic scanning, complex post-processing procedures for lifetime images, and inherent trade-offs among contrast, signal-to-noise ratio, and speed. This study presents a two-photon fluorescence lifetime volumetric projection microscopy using an axially elongated Bessel focus and instant frequency-domain fluorescence lifetime technique, and integrating with a convolutional network to enhance the imaging speed for in vivo neurodynamics mapping.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!