A5037463323- Gene Regulatory Network Analysis
- Cellular Mechanics and Interactions
- Bacterial Genetics and Biotechnology
- Molecular Communication and Nanonetworks
- DNA and Nucleic Acid Chemistry
- Evolutionary Game Theory and Cooperation
- Lipid Membrane Structure and Behavior
- Evolution and Genetic Dynamics
- Photoreceptor and optogenetics research
- Microfluidic and Bio-sensing Technologies
- Neural dynamics and brain function
- Ecosystem dynamics and resilience
- Molecular Junctions and Nanostructures
- Bacteriophages and microbial interactions
- Genetics, Aging, and Longevity in Model Organisms
- Advanced Thermodynamics and Statistical Mechanics
- Cell Image Analysis Techniques
- Spectroscopy and Quantum Chemical Studies
- Receptor Mechanisms and Signaling
- Protein Structure and Dynamics
- Micro and Nano Robotics
- Slime Mold and Myxomycetes Research
- Nonlinear Dynamics and Pattern Formation
- Immune Response and Inflammation
- Bacterial biofilms and quorum sensing
Imperial College London
2016-2025
Imperial Valley College
2024-2025
The London College
2023
Transnational Press London
2017
Institute of Bioinformatics and Applied Biotechnology
2017
Rutgers, The State University of New Jersey
2002-2012
Princeton University
2005-2008
Oak Ridge National Laboratory
2002-2006
Technical University of Munich
1996-2005
Institute of Medical Microbiology and Hygiene
1997-2005
The DNA molecule, well known from biology for containing the genetic code of all living species, has recently caught attention chemists and physicists. A major reason this interest is DNA's potential use in nanoelectronic devices, both as a template assembling nanocircuits an element such circuits. Without question, truly conducting form would have impact on developments nanotechnology. It also been suggested that extended electronic states could play important role biology, e.g., through...
The ratio of the electric and magnetic form factors proton, GEp/GMp, was measured at Thomas Jefferson National Accelerator Facility (JLab) using recoil polarization technique. is directly proportional to transverse longitudinal components proton in elastic $\vec ep \to e\vec p$ reaction. new data presented this article span range 3.5 < Q2 5.6 GeV2 are well described by a linear fit. Also, QF2p/F1p reaches constant value above Q2=2 GeV2.
The formation of germinal centers (GCs) represents a crucial step in the humoral immune response. Recent studies using gene-targeted mice have revealed that cytokines tumor necrosis factor (TNF), lymphotoxin (LT) alpha, and LTbeta, as well their receptors TNF receptor p55 (TNFRp55) LTbetaR play essential roles development GCs. To establish which cell types expression LTbetaR, is required for GC formation, LTbetaR-/-, LTbeta-/-, TNF-/-, B cell-deficient (BCR-/-), wild-type were used to...
Many types of cells are able to accurately sense shallow gradients chemicals across their diameters, allowing the move towards or away from chemical sources. This chemotactic ability relies on remarkable capacity infer particles randomly arriving at cell-surface receptors by diffusion. Whereas physical limits concentration sensing have been explored, there is no theory for gradient sensing. Here, we derive such a theory, using as models perfectly absorbing sphere and monitoring sphere,...
The chemotaxis network in Escherichia coli is remarkable for its sensitivity to small relative changes the concentrations of multiple chemical signals. We present a model signal integration by mixed clusters interacting two-state chemoreceptors. Our results compare favorably obtained Sourjik and Berg with vivo fluorescence resonance energy transfer. Importantly, we identify two distinct regimes behavior, depending on energies states receptors. In regime I, coupling receptors leads high...
The chemotaxis system in the bacterium Escherichia coli is remarkably sensitive to small relative changes concentrations of multiple chemical signals over a broad range ambient concentrations. Interactions among receptors are crucial this sensitivity as precise adaptation, return chemoreceptor activity prestimulus levels constant chemoeffector environment. Precise adaptation relies on methylation and demethylation chemoreceptors by enzymes CheR CheB, respectively. Experiments indicate that...
Precise measurements of the proton electromagnetic form factor ratio $R = \mu_p G_E^p/G_M^p$ using polarization transfer method at Jefferson Lab have revolutionized understanding nucleon structure by revealing strong decrease $R$ with momentum $Q^2$ for $Q^2 \gtrsim 1$ GeV$^2$, in disagreement previous extractions from cross section measurements. In particular, results exposed limits applicability one-photon-exchange approximation and highlighted role quark orbital angular structure. The...
The accuracy by which biological cells sense chemical concentration is ultimately limited the random arrival of particles at receptors diffusion. This fundamental physical limit generally considered to be Berg-Purcell [Biophys. J. 20, 193 (1977)]. Here we derive a lower applying maximum likelihood time series receptor occupancy. increased stems from solely considering unoccupied intervals--disregarding occupied intervals as these do not contain any information about external particle...
Significance To which extent gene regulatory programs are optimized by evolution is one of the fundamental biological questions. Swimming motility costliest bacterial behaviors, but expression genes nevertheless increases when bacteria grow slower on poor carbon sources. Here, we show that competitive fitness benefit provided ability motile to follow gradients secondary nutrients shows similar negative dependence growth rate as investment in motility. Thus, appear pre-invest into behavior...
The chemotaxis network in Escherichia coli is remarkable for its sensitivity to small relative changes the concentrations of multiple chemical signals over a broad range ambient concentrations. Key this an adaptation system that relies on methylation and demethylation (or deamidation) specific modification sites chemoreceptors by enzymes CheR CheB, respectively. It was recently discovered these can access five seven receptors when tethered particular receptor. We show “assistance...
Abstract Containment of intracellularly viable microorganisms requires an intricate cooperation between macrophages and T cells, the most potent mediators known to date being IFN-γ TNF. To identify novel mechanisms involved in combating intracellular infections, experiments were performed mice with selective defects lymphotoxin (LT)/LTβR pathway. When deficient LTα or LTβ challenged intranasally Mycobacterium tuberculosis, they showed a significant increase bacterial loads lungs livers...
Abstract Background Phagocytosis is the fundamental cellular process by which eukaryotic cells bind and engulf particles their cell membrane. Particle engulfment involves particle recognition cell-surface receptors, signaling remodeling of actin cytoskeleton to guide membrane around in a zipper-like fashion. Despite complexity, phagocytosis also depends strongly on biophysical parameters, such as shape, need for actin-driven force generation remains poorly understood. Results Here, we...
Phagocytosis and receptor-mediated endocytosis are vitally important particle uptake mechanisms in many cell types, ranging from single-cell organisms to immune cells. In both processes, engulfment by the depends critically on shape orientation. However, most previous theoretical work has focused only spherical particles hence disregards wide-ranging shapes occurring nature, such as those of bacteria. Here, implementing a simple model one two dimensions, we compare contrast phagocytosis for...
The behaviour of an organism often reflects a strategy for coping with its environment. Such in higher organisms can be reduced to few stereotyped modes movement due physiological limitations, but finding such amoeboid cells is more difficult as they lack these constraints. Here, we examine cell shape and starved Dictyostelium amoebae during migration toward chemoattractant microfluidic chamber. We show that the incredible variety across population variation. Interestingly, use distinct...
Far-from-equilibrium thermodynamics underpins the emergence of life, but how has been a long-outstanding puzzle. Best candidate theories based on maximum entropy production principle could not be unequivocally proven, in part due to complicated physics, unintuitive stochastic thermodynamics, and existence alternative such as minimum principle. Here, we use simple, analytically solvable, one-dimensional bistable chemical system demonstrate validity To generalize multistable system,...
The pathogenesis of mycobacterial infections is associated with the formation granulomas in which both antibacterial protection and tissue damage take place concomitantly. We used murine Mycobacterium avium infection to compare development granulomatous lesions intravenously infected tumor necrosis factor receptor p55 (TNFRp55) gene-deficient (p55(-/-)) mice M. avium-infected syngeneic C57BL/6 (p55(+/+)) mice. Up 5 weeks after either highly virulent strain TMC724 or intermediately SE01,...
ABSTRACT Outer membrane β-barrel proteins in gram-negative bacteria, such as Escherichia coli , must be translocated from their site of synthesis the cytoplasm to periplasm and finally delivered outer membrane. At least a dozen located cytoplasm, periplasm, both inner membranes are required catalyze this complex assembly process. normal growth temperatures conditions transport processes so fast that intermediates cannot detected. Using cells grown at low temperature slow process pulse-chase...