α-tubulin detyrosination fine-tunes kinetochore-microtubule attachments.

Post-translational cycles of α-tubulin detyrosination and tyrosination generate microtubule diversity, the cellular functions of which remain largely unknown. Here we show that α-tubulin detyrosination regulates kinetochore-microtubule attachments to ensure normal chromosome oscillations and timely anaphase onset during mitosis. Remarkably, detyrosinated α-tubulin levels near kinetochore microtubule plus-ends depend on the direction of chromosome motion during metaphase.

CLASP2 recognizes tubulins exposed at the microtubule plus-end in a nucleotide state-sensitive manner.

CLASPs (cytoplasmic linker-associated proteins) are ubiquitous stabilizers of microtubule dynamics, but their molecular targets at the microtubule plus-end are not understood. Using DNA origami-based reconstructions, we show that clusters of human CLASP2 form a load-bearing bond with terminal non-GTP tubulins at the stabilized microtubule tip. This activity relies on the unconventional TOG2 domain of CLASP2, which releases its high-affinity bond with non-GTP dimers upon their conversion into polymerization-competent GTP-tubulins.

Ultrafast Force-Clamp Spectroscopy of Microtubule-Binding Proteins.

Optical trapping has been instrumental for deciphering translocation mechanisms of the force-generating cytoskeletal proteins. However, studies of the dynamic interactions between microtubules (MTs) and MT-associated proteins (MAPs) with no motor activity are lagging. Investigating the motility of MAPs that can diffuse along MT walls is a particular challenge for optical-trapping assays because thermally driven motions rely on weak and highly transient interactions.

Twisted Few-Mode Optical Fiber with Improved Height of Quasi-Step Refractive Index Profile.

This work presents designed and fabricated silica few-mode optical fiber (FMF) with induced twisting 10 and 66 revolutions per meter, core diameter 11 µm, typical "telecommunication" cladding diameter 125 µm, improved height of quasi-step refractive index profile and numerical aperture 0.22. Proposed FMF supports 4 guided modes over "C"-band.

Lithium Ascorbate as a Promising Neuroprotector: Fundamental and Experimental Studies of an Organic Lithium Salt.

Given the observable toxicity of lithium carbonate, neuropharmacology requires effective and non-toxic lithium salts. In particular, these salts can be employed as neuroprotective agents since lithium ions demonstrate neuroprotective properties through inhibition of glycogen synthetase kinase-3β and other target proteins, increasing concentrations of endogenous neurotrofic factors. The results of theoretical and experimental studies of organic lithium salts presented here indicate their potential as neuroprotectors.

Spectral dependence of principal axes in anti-resonant hollow-core fibers with different numbers of capillaries.

We report on measurements highlighting the spectral dependence of the principal axes' angular orientation that is present within three hollow-core fibers samples of various geometries. Hollow-core anti-resonant fibers (ARFs) with six, five, and four capillaries are investigated in several transmission windows. It is shown that the six-capillary fiber structure demonstrates a much smaller shift in the principal axes' orientation, in comparison with five- and four-capillary structures.

Birefringence properties of anti-resonant octagonal-core and nodeless hollow-core fibers.

We present experimental results of birefringence property measurements for two types of negative curvature anti-resonant hollow-core fibers (AR-HCFs). Both AR-HCFs have a core of 50 µm in diameter, providing an effective area of the fundamental guided mode larger than 1000µ. Measurements were carried out at wavelengths of 2.