Biochemical characterization of an ulvan lyase from the marine flavobacterium Formosa agariphila KMM 3901T

Applied Microbiology and Biotechnology - Carbohydrates are the product of carbon dioxide fixation by algae in the ocean. Their polysaccharides are depolymerized by marine bacteria, with a vast...     

The Molecular Basis of Polysaccharide Sulfatase Activity and a Nomenclature for Catalytic Subsites in this Class of Enzyme

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Quantitative Evaluation of Performance in Interventional Neuroradiology: An Integrated Curriculum Featuring Theoretical and Practical Challenges

Purpose

We sought to develop a standardized curriculum capable of assessing key competencies in Interventional Neuroradiology by the use of models and simulators in an objective, quantitative, and efficient way. In this evaluation we analyzed the associations between the practical experience, theoretical knowledge, and the skills lab performance of interventionalists.

Materials and Methods

We evaluated the endovascular skills of 26 participants of the Advanced Course in Endovascular Interventional Neuroradiology of the European Society of Neuroradiology with a set of three tasks (aneurysm coiling and thrombectomy in a virtual simulator and placement of an intra-aneurysmal flow disruptor in a flow model). Practical experience was assessed by a survey. Participants completed a written and oral examination to evaluate theoretical knowledge. Bivariate and multivariate analyses were performed.

Results

In multivariate analysis knowledge of materials and techniques in Interventional Neuroradiology was moderately associated with skills in aneurysm coiling and thrombectomy. Experience in mechanical thrombectomy was moderately associated with thrombectomy skills, while age was negatively associated with thrombectomy skills. We found no significant association between age, sex, or work experience and skills in aneurysm coiling.

Conclusion

Our study gives an example of how an integrated curriculum for reasonable and cost-effective assessment of key competences of an interventional neuroradiologist could look. In addition to traditional assessment of theoretical knowledge practical skills are measured by the use of endovascular simulators yielding objective, quantitative, and constructive data for the evaluation of the current performance status of participants as well as the evolution of their technical competency over time.     

Rotational Diffusion of the α2a Adrenergic Receptor Revealed by FlAsH Labeling in Living Cells

The fluorescein arsenical hairpin binder (FlAsH) shows much promise to determine the relative orientations of protein regions and structures even in living cells and in the plasma membrane. In this study, we characterized FlAsH's photophysical properties by steady-state anisotropy and time-resolved single photon counting for further applications with G-protein coupled receptors. We find that FlAsH has a relatively high initial anisotropy of 0.31 ± 0.01 and a three-component fluorescence lifetime with an average of 4.1 ± 0.1 ns. We characterized the FlAsH fluorophore orientation in the α_2A adrenergic receptor revealing rigid orientations of FlAsH in the membrane plane for rotational correlation times of ∼50 ns in living cells. To elucidate the fluorophore-membrane orientation and rotational correlation time, an anisotropy treatment similar to that of another researcher (Axelrod, D. 1979. Biophys. J. 26:557–573) was developed. The rotational correlation times were observed to increase by up to 16 ns after agonist addition. The rotational correlation time also allowed for a comparison to the theoretical relationship between translational and rotational diffusion (originally proposed by Saffman, P. G., and M. Delbrück. 1975. Proc. Natl. Acad. Sci. USA. 72:3111–3113) and revealed a discrepancy of a factor between 10 and 100.     

Plant-made therapeutics: an emerging platform in South Africa

The field of plant-made therapeutics in South Africa is well established in the form of exploitation of the country's considerable natural plant diversity, both in the use of native plants in traditional herbal medicines over many centuries, and in the more modern extraction of pharmacologically-active compounds from plants, including those known to traditional healers. In recent years, this has been added to by the use of plants for the stable or transient expression of pharmaceutically-important compounds, largely protein-based biologics and vaccines. South Africa has a well-developed plant biotechnology community, as well as a comprehensive legislative framework for the regulation of the exploitation of local botanic resources, and of genetically-modified organisms. The review explores the investigation of both conventional and recombinant plants for pharmaceutical use in South Africa, as well as describing the relevant legislative and regulatory frameworks. Potential opportunities for national projects, as well as factors limiting biopharming in South Africa are discussed.     

Estimation of Immune Cell Densities in Immune Cell Conglomerates: An Approach for High-Throughput Quantification

Background

Determining the correct number of positive immune cells in immunohistological sections of colorectal cancer and other tumor entities is emerging as an important clinical predictor and therapy selector for an individual patient. This task is usually obstructed by cell conglomerates of various sizes. We here show that at least in colorectal cancer the inclusion of immune cell conglomerates is indispensable for estimating reliable patient cell counts. Integrating virtual microscopy and image processing principally allows the high-throughput evaluation of complete tissue slides.

Methodology/Principal findings

For such large-scale systems we demonstrate a robust quantitative image processing algorithm for the reproducible quantification of cell conglomerates on CD3 positive T cells in colorectal cancer. While isolated cells (28 to 80 µm²) are counted directly, the number of cells contained in a conglomerate is estimated by dividing the area of the conglomerate in thin tissues sections (≤6 µm) by the median area covered by an isolated T cell which we determined as 58 µm². We applied our algorithm to large numbers of CD3 positive T cell conglomerates and compared the results to cell counts obtained manually by two independent observers. While especially for high cell counts, the manual counting showed a deviation of up to 400 cells/mm² (41% variation), algorithm-determined T cell numbers generally lay in between the manually observed cell numbers but with perfect reproducibility.

Conclusion

In summary, we recommend our approach as an objective and robust strategy for quantifying immune cell densities in immunohistological sections which can be directly implemented into automated full slide image processing systems.     

Potent dihydroquinolinone dopamine D2 partial agonist/serotonin reuptake inhibitors for the treatment of schizophrenia

A dihydroquinolinone moiety was found to be a potent serotonin reuptake inhibitor pharmacophore when combined with certain amines. This fragment was coupled with selected D₂ ligands to prepare a series of dual acting compounds with attractive in vitro profiles as dopamine D₂ partial agonists and serotonin reuptake inhibitors. Structure–activity studies revealed that the linker plays a key role in contributing to D₂ affinity, function, and SRI activity.     

Biotic interactions improve prediction of boreal bird distributions at macro-scales

Aim The role of biotic interactions in influencing species distributions at macro‐scales remains poorly understood. Here we test whether predictions of distributions for four boreal owl species at two macro‐scales (10 × 10 km and 40 × 40 km grid resolutions) are improved by incorporating interactions with woodpeckers into climate envelope models. Location Finland, northern Europe. Methods Distribution data for four owl and six woodpecker species, along with data for six land cover and three climatic variables, were collated from 2861 10 × 10 km grid cells. Generalized additive models were calibrated using a 50% random sample of the species data from western Finland, and by repeating this procedure 20 times for each of the four owl species. Models were fitted using three sets of explanatory variables: (1) climate only; (2) climate and land cover; and (3) climate, land cover and two woodpecker interaction variables. Models were evaluated using three approaches: (1) examination of explained deviance; (2) four‐fold cross‐validation using the model calibration data; and (3) comparison of predicted and observed values for independent grid cells in eastern Finland. The model accuracy for approaches (2) and (3) was measured using the area under the curve of a receiver operating characteristic plot. Results At 10‐km resolution, inclusion of the distribution of woodpeckers as a predictor variable significantly improved the explanatory power, cross‐validation statistics and the predictive accuracy of the models. Inclusion of land cover led to similar improvements at 10‐km resolution, although these improvements were less apparent at 40‐km resolution for both land cover and biotic interactions. Main conclusions Predictions of species distributions at macro‐scales may be significantly improved by incorporating biotic interactions and land cover variables into models. Our results are important for models used to predict the impacts of climate change, and emphasize the need for comprehensive evaluation of the reliability of species–climate impact models.     

Getting to the inside of cells using metabolic control analysis

Metabolic control analysis can relate control properties of an intact system to kinetic properties (elasticity coefficients) of the enzymes within that system. The method formulating the former as matrix inverse of the latter is elaborated here for the general case and founded in standard metabolic control theory. Then a method is developed that accomplishes the reverse: it is shown that a matrix containing all elasticity coefficients and information concerning the pathway structure equals the inverse of a matrix containing flux and concentration control coefficients. As a consequence, by measuring the control properties of an intact system, one is able to deduce its in situ pathway structure and enzyme kinetic properties: This solves the ever-present question of whether the kinetic properties of enzymes in their isolated state differ from those under the conditions prevailing in the cell.