Production of α-L-iduronidase in maize for the potential treatment of a human lysosomal storage disease

Lysosomal storage diseases are a class of over 70 rare genetic diseases that are amenable to enzyme replacement therapy. Towards developing a plant-based enzyme replacement therapeutic for the lysosomal storage disease mucopolysaccharidosis I, here we expressed α-L-iduronidase in the endosperm of maize seeds by a previously uncharacterized mRNA-targeting-based mechanism. Immunolocalization, cellular fractionation and in situ RT-PCR demonstrate that the α-L-iduronidase protein and mRNA are targeted to endoplasmic reticulum (ER)-derived protein bodies and to protein body-ER regions, respectively, using regulatory (5′-and 3′-UTR) and signal-peptide coding sequences from the γ-zein gene. The maize α-L-iduronidase exhibits high activity, contains high-mannose N-glycans and is amenable to in vitro phosphorylation. This mRNA-based strategy is of widespread importance as plant N-glycan maturation is controlled and the therapeutic protein is generated in a native form. For our target enzyme, the N-glycan structures are appropriate for downstream processing, a prerequisite for its potential as a therapeutic protein.9 page(s

Performance of europium-doped strontium iodide, transparent ceramics and bismuth-loaded polymer scintillators

Recently discovered scintillators for gamma ray spectroscopy, single crystal SrI{sub 2}(Eu), GYGAG(Ce) transparent ceramic and Bismuth-loaded plastics, offer resolution and fabrication advantages compared to commercial scintillators, such as NaI(Tl) and standard PVT plastic. Energy resolution at 662 keV of 2.7% is obtained with SrI{sub 2}(Eu), while 4.5% is obtained with GYGAG(Ce). A new transparent ceramic scintillator for radiographic imaging systems, GLO(Eu) offers high light yield of 70,000 Photons/MeV, high stopping, and low radiation damage. Implementation of single crystal SrI{sub 2}(Eu), Gd-based transparent ceramics, and Bi-loaded plastic scintillators can advance the state-of-the art in ionizing radiation detection systems

Experimental evolution of adaptive divergence under varying degrees of gene flow

Adaptive divergence is the key evolutionary process generating biodiversity by means of natural selection. Yet, the conditions under which it can arise in the presence of gene flow remain contentious. To address this question, we subjected 132 sexually reproducing fission yeast populations, sourced from two independent genetic backgrounds, to disruptive ecological selection and manipulated the level of migration between environments. Contrary to theoretical expectations, adaptive divergence was most pronounced when migration was either absent (allopatry) or maximal (sympatry), but was much reduced at intermediate rates (parapatry and local mating). This effect was apparent across central life-history components (survival, asexual growth and mating) but differed in magnitude between ancestral genetic backgrounds. The evolution of some fitness components was constrained by pervasive negative correlations (trade-off between asexual growth and mating), while others changed direction under the influence of migration (for example, survival and mating). In allopatry, adaptive divergence was mainly conferred by standing genetic variation and resulted in ecological specialization. In sympatry, divergence was mainly mediated by novel mutations enriched in a subset of genes and was characterized by the repeated emergence of two strategies: an ecological generalist and an asexual growth specialist. Multiple loci showed consistent evidence for antagonistic pleiotropy across migration treatments providing a conceptual link between adaptation and divergence. This evolve-and-resequence experiment shows that rapid ecological differentiation can arise even under high rates of gene flow. It further highlights that adaptive trajectories are governed by complex interactions of gene flow, ancestral variation and genetic correlations

Influenza Virus, Overview: Structures, Infection Mechanisms and Antivirals

Hemagglutinin (HA) and neuraminidase (NA) are the two major surface proteins of influenza A virus (IAV). Initial attachment of the virus to the host cell is mediated by the binding of terminal sialic acids (Sia) of glycoconjugates to HA. At the final step of the infectious cycle NA cleaves Sia to ensure virus release from the cell surface. In this overview focus will be given to the structural details of Sia receptor binding and Sia cleavage and how this information in the case of NA has enabled the development of potent sialomimetic drugs by structure-based drug design.Office of the Snr Dep Vice Chancellor, Institute for GlycomicsNo Full Tex

Titration of the BOLD effect: Separation and quantitation of blood volume and oxygenation changes in the human cerebral cortex during neuronal activation and ferumoxide infusion

Most functional magnetic resonance imaging (fMRI) techniques are sensitive to susceptibility variations and rely on the change in blood oxygenation level in response to neuronal activation (BOLD). The BOLD effect is accompanied by a change in cerebral blood flow (rCBF) and cerebral blood volume (rCBV). Intravascular contrast agents, such as magnetite nanoparticles, can be used to measure changes in rCBV. A new measuring protocol has been developed that enables the separate quantification of changes in blood volume and oxygenation levels. A combination of alternating acoustic stimulation blocks and infusion of a superparamagnetic contrast agent offers the possibility to disentangle the competing influences of oxygenation and blood volume changes. Serial blood sampling during infusion was used to assess the actual contrast agent concentration during infusion in order to calculate absolute blood volume changes during neuronal resting and activation states

Arterial first pass gadolinium-CM dynamics as a function of several intravenous saline flush and Gd volumes

This study was performed to evaluate the dynamics of an arterial first pass gadolinium (Gd) contrast medium (CM) bolus at the descending aorta (DAo), depending on various saline flush and Gd volumes. Using an ultra-fast two- dimensional GE-sequence (Siemens Vision®, 1.5-T), 200 sequential cross-sectional images of the addressed vessel (1 slice/s) were obtained. Several saline flush volumes (15 mL, 30 mL, and 60 mL) were applied following the administration of 10 mL Gd (single dose) to a group of 4 normal volunteers (body weight 50–55 kg) using a mechanical MR injector (injection rate = 3.0 mL/s). Additionally, when performing a second test series, the saline volume remained constant, while the Gd volumes were varied from half doses to triple doses (5, 10, 20, and 30 mL Gd were given to every volunteer of the group). The signal intensity versus time (SI/T) curve at a measured region of interest (ROI) within the DAo was calculated. The bolus arrival time (BAT), the maximal signal-to-noise ratio (SNRmax), the bolus time length (BL; 75 and 80 maximum intensity duration), the slope of the SI/T curve, and the areas below the SI/T curve for both the 80 and 75 maximum intensity duration level (INT80 and INT75) were calculated. The increase of saline flush volume from 30 to 60 mL caused significant bolus lengthening of approximately 50 (mean BL = 9.5 s, 10.3 s, and 15.4 s for 15 mL, 30 mL, and 60 mL saline flush volumes, respectively, measured as SI/T duration at the 75 SNRmax level). Using saline flush volumes equal to or higher than 30 mL increased the slope of the SI/T curve. A continuous increase of INT75/80 by using higher saline flush volumes was found. Different saline and Gd volumes did not affect the SNRmax and the BAT. Only the low dose (0.05 mmol/kg Gd) showed a 17–21.6 significantly lower SNRmax. The BL and the INT increased mainly by enlarging of applied Gd volume from single to double dose (BL75 and INT75 were 9.6 s and 1305, 12.3 s and 2121, 38.5 s and 6181, 37.8 s and 6613 for 5, 10, 20, and 30 mL applied Gd volume, respectively). The arterial bolus length benefits from increasing Gd and saline flush volumes due to increased venous bolus length and wash out effects of Gd within the injection site of the vein. Doses larger than a single dose are not needed to increase the SNR in contrast-enhanced magnetic resonance angiography images of the thoracic aorta