Single-strand conformation polymorphism analysis with high throughput modifications, and its use in mutation detection in familial hypercholesterolemia. The IFCC Scientific Division: Committee on Molecular Biology Techniques.

The identification of the specific mutation causing an inherited disease in a patient is the framework for the development of a rationale for therapy and of DNA-based tests for screening relatives. We present here a review of the single-strand conformational polymorphism (SSCP) method, which allows DNA fragments that have been amplified with specific primers and PCR to be scanned rapidly for any sequence variation. The general principles of the method are described, as are the major factors that must be considered in developing an optimal SSCP strategy, namely length of the PCR fragment and the temperature of the gel run. Options for sample denaturing gel characteristics and detection of DNA fragments are discussed. In addition, several modifications are presented that have been developed for high-throughput mutational analysis. The application of these techniques to screen for mutations in the LDL receptor gene in patients with familial hypercholesterolemia are described.     

Temporal and spatial imaging of hydrogen storage materials: watching solvent and hydrogen desorption from aluminium hydride by transmission electron microscopy

An in situ thermal desorption study of solvated aluminum hydride (alane) by transmission electron microscopy and selected area diffraction has permitted characterisation of the structural and morphological changes during desorption of solvent and hydrogen in real-time; this powerful technique for studying hydrogen storage materials complements several others already employed.     

Use of N‐methyliminodiacetic acid boronate esters in suzuki‐miyaura cross‐coupling polymerizations of triarylamine and fluorene monomers

Polytriarylamine copolymers can be prepared by Suzuki‐Miyaura cross‐coupling reactions of bis N‐methyliminodiacetic acid (MIDA) boronate ester substituted arylamines with dibromo arenes. The roles of solvent composition, temperature, reaction time, and co‐monomer structure were examined and (co)polymers prepared containing 9, 9‐dioctylfluorene (F8), 4‐sec‐butyl or 4‐octylphenyl diphenyl amine (TFB), and N, N′‐bis(4‐octylphenyl)‐N, N′‐diphenyl phenylenediamine (PTB) units, using a Pd(OAc)₂/2‐dicyclohexylphosphino‐2′,6′‐dimethoxybiphenyl (SPhos) catalyst system. The performance of a di‐functionalized MIDA boronate ester monomer was compared with that of an equivalent pinacol boronate ester. Higher molar mass polymers were produced from reactions starting with a difunctionalized pinacol boronate ester monomer than the equivalent difunctionalized MIDA boronate ester monomer in biphase solvent mixtures (toluene/dioxane/water). Matrix‐assisted laser desorption/ionization mass spectroscopic analysis revealed that polymeric structures rich in residues associated with the starting MIDA monomer were present, suggesting that homo‐coupling of the boronate ester must be occurring to the detriment of cross‐coupling in the step‐growth polymerization. However, when comparable reactions of the two boronate monomers with a dibromo fluorene monomer were completed in a single phase solvent mixture (dioxane + water), high molar mass polymers with relatively narrow distribution ranges were obtained after only 4 h of reaction. © 2017 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2798–2806     

In-silico guided discovery of novel CCR9 antagonists

Antagonism of CCR9 is a promising mechanism for treatment of inflammatory bowel disease, including ulcerative colitis and Crohn’s disease. There is limited experimental data on CCR9 and its ligands, complicating efforts to identify new small molecule antagonists. We present here results of a successful virtual screening and rational hit-to-lead campaign that led to the discovery and initial optimization of novel CCR9 antagonists. This work uses a novel data fusion strategy to integrate the output of multiple computational tools, such as 2D similarity search, shape similarity, pharmacophore searching, and molecular docking, as well as the identification and incorporation of privileged chemokine fragments. The application of various ranking strategies, which combined consensus and parallel selection methods to achieve a balance of enrichment and novelty, resulted in 198 virtual screening hits in total, with an overall hit rate of 18%. Several hits were developed into early leads through targeted synthesis and purchase of analogs.     

Action of braid groups on determinantal ideals, compact spaces and a stratification of Teichmüller space

We show that for n≥3 there is an action of the braid group B _n on the determinantal ideals of a certain n×n symmetric matrix with algebraically independent entries off the diagonal and 2s on the diagonal. We show how this action gives rise to an action of B _n on certain compact subspaces of some Euclidean spaces of dimension . These subspaces are real semi-algebraic varieties and include spheres of dimension -1 on which the kernel of the action of B _n is the centre of B _n . We investigate the action of B _n on these subspaces. We also show how a finite number of disjoint copies of the Teichmüller space for the n-punctured disc is naturally a subset of this ℝ and how this cover (in the broad sense) of Teichmüller space is a union of non-trivial B _n -invariant subspaces. The action of B _n on this cover of Teichmüller space is via polynomial automorphisms. For the case n=3 we show how to define modular forms on the 3-dimensional Teichmüller space relative to the action of B ₃. Oblatum 29-V-2000 & 7-XI-2000?Published online: 5 March 2001     

Intersection-Number Operators for Curves on Discs II

Let the braid group B _n act as (isotopy classes of) diffeomorphisms of an n-punctured disc D _n . Then there is an associated action of B _n on a polynomial algebra R = ?[a ₁,..., a _N ] and a way of representing simple closed curves on D _n as elements of R. Fix k ∈ 2?. Using this approach we show that the image in Aut(R) of each Dehn twist τ about a simple closed γ in D _n satisfies a kind of characteristic equation when its action is restricted to the image in R of the set of curves γ having geometric intersection number k with γ.     

A Conventional Surfactant Becomes CO2‐Responsive in the Presence of Switchable Water Additives

We have developed a new benign means of reversibly breaking emulsions and latexes by using “switchable water”, an aqueous solution of switchable ionic strength. The conventional surfactant sodium dodecyl sulfate (SDS) is not normally stimuli‐responsive when CO₂ is used as the stimulus but becomes CO₂‐responsive or “switchable” in the presence of a switchable water additive. In particular, changes in the air/water surface tension and oil/water interfacial tension can be triggered by addition and removal of CO₂. A switchable water additive, N,N‐dimethylethanolamine (DMEA), was found to be an effective and efficient additive for the reversible reduction of interfacial tension and can lower the tension of the dodecane/water interface in the presence of SDS surfactant to ultra‐low values at very low additive concentrations. Switchable water was successfully used to reversibly break an emulsion containing SDS as surfactant, and dodecane as organic liquid. Also, the addition of CO₂ and switchable water can result in aggregation of polystyrene (PS) latexes; the later removal of CO₂ neutralizes the DMEA and decreases the ionic strength allowing for the aggregated PS latex to be redispersed and recovered in its original state.     

Single particle tracking as a method to resolve differences in highly colocalized proteins

Single particle tracking fluorescence microscopy was used to study two late endosomal proteins, Rab7 and LAMP1, that appear to be highly colocalized in static fluorescence microscopy images. Imaging these proteins simultaneously reveals that Rab7 and LAMP1 undergo periods of separation within the cell. Single particle tracking carried out during these periods of separation shows that Rab7-vesicles have greater velocities, but undergo less efficient transport than LAMP1-vesicles. This research demonstrates the use of single particle tracking as a tool to resolve functional differences in highly colocalized proteins in intact live cells.