The tryptophan system present in Escherichia coli represents an important regulatory unit described by multiple feedback loops. The role of these feedback loops is crucial for the analysis of the dynamical behavior of the tryptophan synthesis. We analyze the robust stability of this system which models the dynamics of both fast state, such as transcription and synthesis of free operator, and slow state, such as translation and tryptophan synthesis under consideration of nonlinear uncertainties. In addition, we analyze the role of these feedback loops as key design components of this regulatory unit responsible for its physiological performance. The range of allowed parameter perturbations and the conditions that ensure the existence of asymptotically stable equilibria of the perturbed system are determined. We also analyze two important alternate regulatory designs for the tryptophan synthesis pathway and derive the stability conditions.
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Sensors (Basel)
January 2025
Departamento de Ingeniería Electrónica, Universidad de Sevilla, 41092 Seville, Spain.
Variable-speed electrical drive control typically relies upon a two-loop scheme, one for torque/speed and another for stator current control. In modern drive control methods, the actual mechanical speed is needed for both loops. In practical applications, the speed is often acquired by incremental rotary encoders.
View Article and Find Full Text PDFBMC Biol
January 2025
Department of Biology, Section of Zoophysiology, Aarhus University, Aarhus, 8000, Denmark.
Background: Echolocating bats face an intense arms race with insect prey that can detect bat calls and initiate evasive maneuvers. Their high closing speeds and short biosonar ranges leave bats with only a few 100 ms between detection and capture, suggesting a reactive sensory-motor operation that might preclude tracking of escaping prey. Here we test this hypothesis using greater mouse-eared bats (Myotis myotis) as a model species.
View Article and Find Full Text PDFJ Control Release
January 2025
Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China.. Electronic address:
Sepsis is a life-threatening disease characterized by excessive systemic inflammation and coagulopathy. Platelets and neutrophils form a "dangerous alliance" through crosstalk, promoting the inflammatory cytokine storm and coagulation disorders during sepsis. Platelet-neutrophil crosstalk leads to the formation of platelet-neutrophil complexes (PNCs), which are the central "protagonists" of this "dangerous alliance.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Max Perutz Labs, Vienna Biocenter Campus, Vienna 1030, Austria.
RNA G-quadruplexes (rG4s), the four-stranded structures formed by guanine-rich RNA sequences, are recognized by regions in RNA-binding proteins (RBPs) that are enriched in arginine-glycine repeats (RGG motifs). Importantly, arginine and glycine are encoded by guanine-rich codons, suggesting that some RGG motifs may both be encoded by and interact with rG4s in autogenous messenger RNAs (mRNAs). By analyzing transcriptome-wide rG4 datasets, we show that hundreds of RGG motifs in humans are at least partly encoded by rG4s, with an increased incidence for longer RGG motifs (~10 or more residues).
View Article and Find Full Text PDFProteomes
January 2025
Instituto de Matemática e Estatística, Departamento de Ciência da Computação, Universidade de São Paulo, Rua do Matão 1010, São Paulo 05508-090, SP, Brazil.
The tumor suppressor p53, in its wild-type form, plays a central role in cellular homeostasis by regulating senescence, apoptosis, and autophagy within the DNA damage response (DDR). Recent findings suggest that wild-type p53 also governs ferroptosis, an iron-dependent cell death process driven by lipid peroxidation. Post-translational modifications of p53 generate proteoforms that significantly enhance its functional diversity in regulating these mechanisms.
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