Heat application in live cell imaging.

Thermal heating of biological samples allows to reversibly manipulate cellular processes with high temporal and spatial resolution. Manifold heating techniques in combination with live-cell imaging were developed, commonly tailored to customized applications. They include Peltier elements and microfluidics for homogenous sample heating as well as infrared lasers and radiation absorption by nanostructures for spot heating.

Fluorescence changes in carbon nanotube sensors correlate with THz absorption of hydration.

Single wall carbon nanotubes (SWCNTs) functionalized with (bio-)polymers such as DNA are soluble in water and sense analytes by analyte-specific changes of their intrinsic fluorescence. Such SWCNT-based (bio-)sensors translate the binding of a molecule (molecular recognition) into a measurable optical signal. This signal transduction is crucial for all types of molecular sensors to achieve high sensitivities.

Stochastic Formation of Quantum Defects in Carbon Nanotubes.

Small perturbations in the structure of materials significantly affect their properties. One example is single wall carbon nanotubes (SWCNTs), which exhibit chirality-dependent near-infrared (NIR) fluorescence. They can be modified with quantum defects through the reaction with diazonium salts, and the number or distribution of these defects determines their photophysics.

Near-Infrared Fluorescent Biosensors Based on Covalent DNA Anchors.

Semiconducting single-walled carbon nanotubes (SWCNTs) are versatile near-infrared (NIR) fluorophores. They are noncovalently modified to create sensors that change their fluorescence when interacting with biomolecules. However, noncovalent chemistry has several limitations and prevents a consistent way to molecular recognition and reliable signal transduction.

LPS-aggregating proteins GBP1 and GBP2 are each sufficient to enhance caspase-4 activation both in cellulo and in vitro.

The gamma-interferon (IFNγ)-inducible guanylate-binding proteins (GBPs) promote host defense against gram-negative cytosolic bacteria in part through the induction of an inflammatory cell death pathway called pyroptosis. To activate pyroptosis, GBPs facilitate sensing of the gram-negative bacterial outer membrane component lipopolysaccharide (LPS) by the noncanonical caspase-4 inflammasome. There are seven human GBP paralogs, and it is unclear how each GBP contributes to LPS sensing and pyroptosis induction.

Near-Infrared Fluorescence Lifetime Imaging of Biomolecules with Carbon Nanotubes.

Single-walled carbon nanotubes (SWCNTs) are versatile near infrared (NIR) fluorescent building blocks for biosensors. Their surface is chemically tailored to respond to analytes by a change in fluorescence. However, intensity-based signals are easily affected by external factors such as sample movements.

Structural requirements for membrane binding of human guanylate-binding protein 1.

Human guanylate-binding protein 1 (hGBP1) is a key player in innate immunity and fights diverse intracellular microbial pathogens. Its antimicrobial functions depend on hGBP1's GTP binding- and hydrolysis-induced abilities to form large, structured polymers and to attach to lipid membranes. Crucial for both of these biochemical features is the nucleotide-controlled release of the C terminally located farnesyl moiety.

Purification of Farnesylated hGBP1 and Characterization of Its Polymerization and Membrane Binding.

The human guanylate-binding protein 1 (hGBP1) is the best characterized isoform of the seven human GBPs belonging to the superfamily of dynamin-like proteins (DLPs). As known for other DLPs, hGBP1 also exhibits antiviral and antimicrobial activity within the cell. hGBP 1, like hGBPs 2 and 5, carries a CAAX motive at the C-terminus leading to isoprenylation in the living cells.

Direct binding of polymeric GBP1 to LPS disrupts bacterial cell envelope functions.

In the outer membrane of gram-negative bacteria, O-antigen segments of lipopolysaccharide (LPS) form a chemomechanical barrier, whereas lipid A moieties anchor LPS molecules. Upon infection, human guanylate binding protein-1 (hGBP1) colocalizes with intracellular gram-negative bacterial pathogens, facilitates bacterial killing, promotes activation of the lipid A sensor caspase-4, and blocks actin-driven dissemination of the enteric pathogen Shigella. The underlying molecular mechanism for hGBP1's diverse antimicrobial functions is unknown.

The Molecular Mechanism of Polymer Formation of Farnesylated Human Guanylate-binding Protein 1.

The human guanylate-binding protein 1 (hGBP1) belongs to the dynamin superfamily proteins and represents a key player in the innate immune response. Farnesylation at the C-terminus is required for hGBP1's activity against microbial pathogens, as well as for its antiproliferative and antitumor activity. The farnesylated hGBP1 (hGBP1) retains many characteristics of the extensively studied nonfarnesylated protein and gains additional abilities like binding to lipid membranes and formation of hGBP1 polymers.

Protein Folding Modulation in Cells Subject to Differentiation and Stress.

Cytomimetic media are used to mimic the physicochemical properties of the cellular milieu in an experiment. The motivation is that compared to entire cells, they can be used efficiently in combination with a broad range of experimental techniques. However, the development and use of cytomimetic media is hampered by the lack of in-cell data that could be used as a hallmark to directly evaluate and improve the performance of cytomimetic media in different applications.