Three-dimensional holographic optical manipulation through a high-numerical-aperture soft-glass multimode fibre

Holographic optical tweezers (HOT) hold great promise for many applications in biophotonics, allowing the creation and measurement of minuscule forces on biomolecules, molecular motors and cells. Geometries used in HOT currently rely on bulk optics, and their exploitation in vivo is compromised by the optically turbid nature of tissues. We present an alternative HOT approach in which multiple three-dimensional (3D) traps are introduced through a high-numerical-aperture multimode optical fibre, thus enabling an equally versatile means of manipulation through channels having cross-section comparable to the size of a single cell. Our work demonstrates real-time manipulation of 3D arrangements of micro-objects, as well as manipulation inside otherwise inaccessible cavities. We show that the traps can be formed over fibre lengths exceeding 100 mm and positioned with nanometric resolution. The results provide the basis for holographic manipulation and other high-numerical-aperture techniques, including advanced microscopy, through single-core-fibre endoscopes deep inside living tissues and other complex environments

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field

IGF-1R associates with adverse outcomes after radical radiotherapy for prostate cancer.

Background Activated type 1 insulin-like growth factor receptors (IGF-1Rs) undergo internalisation and nuclear translocation, promoting cell survival. We previously reported that IGF-1R inhibition delays DNA damage repair, sensitising prostate cancer cells to ionising radiation. Here we tested the clinical relevance of these findings.Methods We assessed associations between IGF-1R and clinical outcomes by immunohistochemistry in diagnostic biopsies of 136 men treated with 55-70 Gy external beam radiotherapy for prostate cancer, comparing results with publicly available transcriptional data in surgically treated patients.Results Following radiotherapy, overall recurrence-free survival was shorter in patients whose tumours contained high total, cytoplasmic and internalised (nuclear/cytoplasmic) IGF-1R. High total IGF-1R associated with high primary Gleason grade and risk of metastasis, and cytoplasmic and internalised IGF-1R with biochemical recurrence, which includes patients experiencing local recurrence within the radiation field indicating radioresistance. In multivariate analysis, cytoplasmic, internalised and total IGF-1R were independently associated with risk of overall recurrence, and cytoplasmic IGF-1R was an independent predictor of biochemical recurrence post radiotherapy. Insulin-like growth factor receptors expression did not associate with biochemical recurrence after radical prostatectomy.Conclusions These data reveal increased risk of post-radiotherapy recurrence in men whose prostate cancers contain high levels of total or cytoplasmic IGF-1R

Proximity Labeling for the Identification of Coronavirus-Host Protein Interactions.

Biotin-based proximity labeling circumvents major pitfalls of classical biochemical approaches to identify protein-protein interactions. It consists of enzyme-catalyzed biotin tags ubiquitously apposed on proteins located in close proximity of the labeling enzyme, followed by affinity purification and identification of biotinylated proteins by mass spectrometry. Here we outline the methods by which the molecular microenvironment of the coronavirus replicase/transcriptase complex (RTC), i.e., proteins located within a close perimeter of the RTC, can be determined by different proximity labeling approaches using BirAR118G (BioID), TurboID, and APEX2. These factors represent a molecular signature of coronavirus RTCs and likely contribute to the viral life cycle, thereby constituting attractive targets for the development of antiviral intervention strategies

Experimental demonstration of optical transport, sorting and self-arrangement using a 'tractor beam'

Following the Keplerian idea of optical forces, one would intuitively expect that an object illuminated by sunlight radiation or a laser beam will be accelerated along the direction of photon flow. Recent theoretical studies1, 2, 3, 4, 5 have shown that small particles can be pulled by light beams against the photon stream, even in beams with uniform optical intensity along the propagation axis. Here, we present a geometry to generate such a ‘tractor beam’, and experimentally demonstrate its functionality using spherical microparticles of various sizes, as well as its enhancement with optically self-arranged structures of microparticles. In addition to the pulling of the particles, we also demonstrate that their two-dimensional motion and one-dimensional sorting may be controlled conveniently by rotation of the polarization of the linearly polarized incident beam. The relative simplicity of this geometry could serve to encourage its widespread application, and ongoing investigations will broaden the understanding of the light–matter interaction through studies combining more interacting micro-objects with various properties