Fast, streamlined fluorescence nanoscopy resolves rearrangements of SNARE and cargo proteins in platelets co-incubated with cancer cells.

Background: Increasing evidence suggests that platelets play a central role in cancer progression, with altered storage and selective release from platelets of specific tumor-promoting proteins as a major mechanism. Fluorescence-based super-resolution microscopy (SRM) can resolve nanoscale spatial distribution patterns of such proteins, and how they are altered in platelets upon different activations. Analysing such alterations by SRM thus represents a promising, minimally invasive strategy for platelet-based diagnosis and monitoring of cancer progression.

Capillary leakage provides nutrients and antioxidants for rapid pneumococcal proliferation in influenza-infected lower airways.

Influenza A virus (IAV)-related mortality is often due to secondary bacterial infections, primarily by pneumococci. Here, we study how IAV-modulated changes in the lungs affect bacterial replication in the lower respiratory tract (LRT). Bronchoalveolar lavages (BALs) from coinfected mice showed rapid bacterial proliferation 4 to 6 h after pneumococcal challenge.

Cumulative effects of photobleaching in volumetric STED imaging-artefacts and possible benefits.

In stimulated emission depletion (STED) imaging, the excitation and depletion laser beams extend well beyond the focal plane in the imaged sample. We investigated how photobleaching resulting from this irradiation can affect STED images, by acquiring 3D images of fluorescent polystyrene beads using a 2D STED microscope, and applying different Z pixel sizes, scanning speeds, resulting in different laser light doses. While higher STED beam irradiances can increase the spatial resolution, they can also significantly increase photobleaching and thereby reduce signal-to-background levels.

Polymeric, Cost-Effective, Dopant-Free Hole Transport Materials for Efficient and Stable Perovskite Solar Cells.

Perovskite solar cells (PSCs) has skyrocketed in the past decade to an unprecedented level due to their outstanding photoelectric properties and facile processability. However, the utilization of expensive hole transport materials (HTMs) and the inevitable instability instigated by the deliquescent dopants represent major concerns hindering further commercialization. Here, a series of low-cost, conjugated polymers are designed and applied as dopant-free HTMs in PSCs, featuring tuned energy levels, good temperature and humidity resistivity, and excellent photoelectric properties.

Super-resolution microscopy can identify specific protein distribution patterns in platelets incubated with cancer cells.

Protein contents in platelets are frequently changed upon tumor development and metastasis. However, how cancer cells can influence protein-selective redistribution and release within platelets, thereby promoting tumor development, remains largely elusive. With fluorescence-based super-resolution stimulated emission depletion (STED) imaging we reveal how specific proteins, implicated in tumor progression and metastasis, re-distribute within platelets, when subject to soluble activators (thrombin, adenosine diphosphate and thromboxane A2), and when incubated with cancer (MCF-7, MDA-MB-231, EFO21) or non-cancer cells (184A1, MCF10A).

On the decay time of upconversion luminescence.

In this study, we systematically investigate the decay characteristics of upconversion luminescence (UCL) under anti-Stokes excitation through numerical simulations based on rate-equation models. We find that a UCL decay profile generally involves contributions from the sensitizer's excited-state lifetime, energy transfer and cross-relaxation processes. It should thus be regarded as the overall temporal response of the whole upconversion system to the excitation function rather than the intrinsic lifetime of the luminescence emitting state.

Factor H binding proteins protect division septa on encapsulated Streptococcus pneumoniae against complement C3b deposition and amplification.

Streptococcus pneumoniae evades C3-mediated opsonization and effector functions by expressing an immuno-protective polysaccharide capsule and Factor H (FH)-binding proteins. Here we use super-resolution microscopy, mutants and functional analysis to show how these two defense mechanisms are functionally and spatially coordinated on the bacterial cell surface. We show that the pneumococcal capsule is less abundant at the cell wall septum, providing C3/C3b entry to underlying nucleophilic targets.

In Situ Monitoring of p53 Protein and MDM2 Protein Interaction in Single Living Cells Using Single-Molecule Fluorescence Spectroscopy.

Protein-protein interactions play a central role in signal transduction, transcription regulations, enzymatic activity, and protein synthesis. The p53 protein is a key transcription factor, and its activity is precisely regulated by the p53-MDM2 interaction. Although the p53-MDM2 interaction has been studied, it is still not clear how p53 structures and external factors influence the p53-MDM2 interaction in living cells.

Platelet protein biomarker panel for ovarian cancer diagnosis.

Background: Platelets support cancer growth and spread making platelet proteins candidates in the search for biomarkers.

Methods: Two-dimensional (2D) gel electrophoresis, Partial Least Squares Discriminant Analysis (PLS-DA), Western blot, DigiWest.

Results: PLS-DA of platelet protein expression in 2D gels suggested differences between the International Federation of Gynaecology and Obstetrics (FIGO) stages III-IV of ovarian cancer, compared to benign adnexal lesions with a sensitivity of 96% and a specificity of 88%.

The lateral distance between a proton pump and ATP synthase determines the ATP-synthesis rate.

We have investigated the effect of lipid composition on interactions between cytochrome bo and ATP-synthase, and the ATP-synthesis activity driven by proton pumping. The two proteins were labeled by fluorescent probes and co-reconstituted in large (d ≅ 100 nm) or giant (d ≅ 10 µm) unilamellar lipid vesicles. Interactions were investigated using fluorescence correlation/cross-correlation spectroscopy and the activity was determined by measuring ATP production, driven by electron-proton transfer, as a function of time.

pIgR and PECAM-1 bind to pneumococcal adhesins RrgA and PspC mediating bacterial brain invasion.

is the main cause of bacterial meningitis, a life-threating disease with a high case fatality rate despite treatment with antibiotics. Pneumococci cause meningitis by invading the blood and penetrating the blood-brain barrier (BBB). Using stimulated emission depletion (STED) super-resolution microscopy of brain biopsies from patients who died of pneumococcal meningitis, we observe that pneumococci colocalize with the two BBB endothelial receptors: polymeric immunoglobulin receptor (pIgR) and platelet endothelial cell adhesion molecule (PECAM-1).

Protonation Dynamics on Lipid Nanodiscs: Influence of the Membrane Surface Area and External Buffers.

Lipid membrane surfaces can act as proton-collecting antennae, accelerating proton uptake by membrane-bound proton transporters. We investigated this phenomenon in lipid nanodiscs (NDs) at equilibrium on a local scale, analyzing fluorescence fluctuations of individual pH-sensitive fluorophores at the membrane surface by fluorescence correlation spectroscopy (FCS). The protonation rate of the fluorophores was ∼100-fold higher when located at 9- and 12-nm diameter NDs, compared to when in solution, indicating that the proton-collecting antenna effect is maximal already for a membrane area of ∼60 nm(2).

Scanning inverse fluorescence correlation spectroscopy.

Scanning Inverse Fluorescence Correlation Spectroscopy (siFCS) is introduced to determine the absolute size of nanodomains on surfaces. We describe here equations for obtaining the domain size from cross- and auto-correlation functions, measurement simulations which enabled testing of these equations, and measurements on model surfaces mimicking membranes containing nanodomains. Using a confocal microscope of 270 nm resolution the size of 250 nm domains were estimated by siFCS to 257 ± 12 nm diameter, and 40 nm domains were estimated to 65 ± 26 nm diameter.