Combining M-FISH and Quantum Dot technology for fast chromosomal assignment of transgenic insertions

<p>Abstract</p> <p>Background</p> <p>Physical mapping of transgenic insertions by Fluorescence in situ Hybridization (FISH) is a reliable and cost-effective technique. Chromosomal assignment is commonly achieved either by concurrent G-banding or by a multi-color FISH approach consisting of iteratively co-hybridizing the transgenic sequence of interest with one or more chromosome-specific probes at a time, until the location of the transgenic insertion is identified.</p> <p>Results</p> <p>Here we report a technical development for fast chromosomal assignment of transgenic insertions at the single cell level in mouse and rat models. This comprises a simplified 'single denaturation mixed hybridization' procedure that combines multi-color karyotyping by Multiplex FISH (M-FISH), for simultaneous and unambiguous identification of all chromosomes at once, and the use of a Quantum Dot (QD) conjugate for the transgene detection.</p> <p>Conclusions</p> <p>Although the exploitation of the unique optical properties of QD nanocrystals, such as photo-stability and brightness, to improve FISH performance generally has been previously investigated, to our knowledge this is the first report of a purpose-designed molecular cytogenetic protocol in which the combined use of QDs and standard organic fluorophores is specifically tailored to assist gene transfer technology.</p

The effect of substrate clamping on the paraelectric to antiferroelectric phase transition in Nd-doped BiFeO₃ thin films

Thin films were deposited on Pt/Ti/SiO₂/Si substrates using pulsed laser deposition from a target with a composition (Bi₀.₈₂₅Nd₀.₁₇₅Fe₀.₉₇Ti₀.₀₃O₃) with 5 mol% excess Bi₂O₃ within the antiferroelectric (AFE) region of the NdFeO₃-BiFeO₃ phase diagram. However, Raman spectroscopy and transmission electron microscopy (TEM) revealed that films consisted of a mosaic microstructure in which (AFE), ferroelectric (FE) and paraelectric (PE) phases coexisted. Variation in the spatial distribution of Nd is typically greater in bulk ceramics than in thin films and therefore, the absence of single phase AFE cannot be attributed to local changes in composition. Instead, it is proposed that clamping due to mismatch in thermal expansion coefficient with the substrate suppresses the large volume change associated with the PE-FE and PE-AFE transition in bulk and its absence in the thin film prevents an avalanche-like transition throughout grains, which in bulk sustains single phase AFE, irrespective of local deviations in the Nd concentration

Surface magnetism in iron, cobalt, and nickel

We have calculated magnetic moments, work functions, and surface energies for several of the most closely packed surfaces of iron, cobalt, and nickel by means of a spin-polarized Green’s-function technique based on the linear muffin-tin orbitals method within the tight-binding and atomic sphere approximations. We find enhanced spin moments at all the surfaces considered except for Ni fcc(111), where the moment at the surface reverts to its bulk value. This is in close agreement with earlier slab calculations. In addition, we find that the calculated work functions and surface energies agree with experimental values to within 10%, which may be considered most satisfactory in view of the computational efficiency of the Green’s function technique. Exchange and correlation have been treated wihtin the local spin-density approximation and we have considered three different parametrizations of the original many-body data. We find that the calculated work functions depend as much on the choice of this parametrization as on the effect of spin polarization

Pediatric Cardiac Intensive Care Society Statement: caring for children with critical cardiac disease across the globe

10.1017/S1047951117002517Cardiology in the young27S6S1-S

CNTF gene therapy confers lifelong neuroprotection in a mouse model of human retinitis pigmentosa.

The long-term outcome of neuroprotection as a therapeutic strategy for preventing cell death in neurodegenerative disorders remains unknown, primarily due to slow disease progression and the inherent difficulty of assessing neuronal survival in vivo. Employing a murine model of retinal disease, we demonstrate that ciliary neurotrophic factor (CNTF) confers life-long protection against photoreceptor degeneration. Repetitive retinal imaging allowed the survival of intrinsically fluorescent cone photoreceptors to be quantified in vivo. Imaging of the visual cortex and assessment of visually-evoked behavioural responses demonstrated that surviving cones retain function and signal correctly to the brain. The mechanisms underlying CNTF-mediated neuroprotection were explored through transcriptome analysis, revealing widespread up-regulation of proteolysis inhibitors, which may prevent cellular/extracellular matrix degradation and complement activation in neurodegenerative diseases. These findings provide insights into potential novel therapeutic avenues for diseases such as retinitis pigmentosa and amyotrophic lateral sclerosis, for which CNTF has been evaluated unsuccessfully in clinical trials.Molecular Therapy (2015); doi:10.1038/mt.2015.68

Characterization of a Dominant Cone Degeneration in a Green Fluorescent Protein–Reporter Mouse with Disruption of Loci Associated with Human Dominant Retinal Dystrophy

The authors characterized a dominant cone degeneration in the cone green fluorescent protein (GFP) reporter mouse that is not mediated by GFP toxicity. Transgenic insertion has been mapped to chromosome 10 and disrupts loci that in humans are associated with dominant cone dystrophies