Ciliary Beating Compartmentalizes Cerebrospinal Fluid Flow in the Brain and Regulates Ventricular Development

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A novel knowledge-based approach to design inorganic-binding peptides

MOTIVATION: The discovery of solid-binding peptide sequences is accelerating along with their practical applications in biotechnology and materials sciences. A better understanding of the relationships between the peptide sequences and their binding affinities or specificities will enable further design of novel peptides with selected properties of interest both in engineering and medicine. RESULTS: A bioinformatics approach was developed to classify peptides selected by in vivo techniques according to their inorganic solid-binding properties. Our approach performs all-against-all comparisons of experimentally selected peptides with short amino acid sequences that were categorized for their binding affinity and scores the alignments using sequence similarity scoring matrices. We generated novel scoring matrices that optimize the similarities within the strong-binding peptide sequences and the differences between the strong- and weak-binding peptide sequences. Using the scoring matrices thus generated, a given peptide is classified based on the sequence similarity to a set of experimentally selected peptides. We demonstrate the new approach by classifying experimentally characterized quartz-binding peptides and computationally designing new sequences with specific affinities. Experimental verifications of binding of these computationally designed peptides confirm our predictions with high accuracy. We further show that our approach is a general one and can be used to design new sequences that bind to a given inorganic solid with predictable and enhanced affinity.     

The Effects of Environmental Risk Factors on City Life Cycle: A Link Analysis

ABSTRACT

Due to rapid industrialization and urbanization, social economy develops in an unparalleled speed, while it certainly fosters the consumption of natural resources and the pressure to protect the ecological environment. Hence, there is a two-way relationship between the well-being of humans and the natural environment. In this study, link analysis techniques along with multivariate statistical analysis were employed to discover the effects of environmental risk factors on city life cycle, where suicides, immigration, and emigration were considered as the fundamental indicators of how cities evolve. Association rules, classification trees, MANOVA, and linear discriminant analysis were applied to data on air quality, socioeconomic development, and demographical factors belonging to the cities of Turkey. The results indicate that socioeconomic development levels of cities differ along attraction and life satisfaction dimensions. People tend to choose a city with better development level and better air quality in order to increase their life satisfaction. Additionally, developed cities are less likely to have issues with air quality and citizens who live in a poorly developed city are least satisfied with their lives.     

The ROCK Inhibitor Y-27632 Improves Recovery of Human Embryonic Stem Cells after Fluorescence-Activated Cell Sorting with Multiple Cell Surface Markers

Background

Due to the inherent sensitivity of human embryonic stem cells (hESCs) to manipulations, the recovery and survival of hESCs after fluorescence-activated cell sorting (FACS) can be low. Additionally, a well characterized and robust methodology for performing FACS on hESCs using multiple-cell surface markers has not been described. The p160-Rho-associated coiled kinase (ROCK) inhibitor, Y-27632, previously has been identified as enhancing survival of hESCs upon single-cell dissociation, as well as enhancing recovery from cryopreservation. Here we examined the application of Y-27632 to hESCs after FACS to improve survival in both feeder-dependent and feeder-independent growth conditions.

Methodology/Principal Findings

HESCs were sorted using markers for SSEA-3, TRA-1-81, and SSEA-1. Cells were plated after sorting for 24 hours in either the presence or the absence of Y-27632. In both feeder-dependent and feeder-independent conditions, cell survival was greater when Y-27632 was applied to the hESCs after sort. Specifically, treatment of cells with Y-27632 improved post-sort recovery up to four fold. To determine the long-term effects of sorting with and without the application of Y-27632, hESCs were further analyzed. Specifically, hESCs sorted with and without the addition of Y-27632 retained normal morphology, expressed hESC-specific markers as measured by immunocytochemistry and flow cytometry, and maintained a stable karyotype. In addition, the hESCs could differentiate into three germ layers in vitro and in vivo in both feeder-dependent and feeder-independent growth conditions.

Conclusions/Significance

The application of Y-27632 to hESCs after cell sorting improves cell recovery with no observed effect on pluripotency, and enables the consistent recovery of hESCs by FACS using multiple surface markers. This improved methodology for cell sorting of hESCs will aid many applications such as removal of hESCs from secondary cell types, identification and isolation of stem cell subpopulations, and generation of single cell clones. Finally, these results demonstrate an additional application of ROCK inhibition to hESC research.     

Quantum dots decorated photoanodes in bioelectrochemical fuel cells: Enhanced electricity generation using green algae

The power performance of the bio-electrochemical fuel cells (BEFCs) depends mainly on the energy harvesting ability of the anode material. The anode materials with low bandgap energy and high electrochemical stability are highly desirable in the BEFCs. To address this issue, a novel anode is designed using indium tin oxide (ITO) modified by chromium oxide quantum dots (CQDs). The CQDs were synthesized using facile and advanced pulsed laser ablation in liquid (PLAL) technique. The combination of ITO and CQDs improved the optical properties of the photoanode by exhibiting a broad range of absorption in the visible to UV region. A systematic study has been performed to optimize the amount of CQDs and green Algae (Alg) film grown using the drop casting method. Chlorophyll (a, b, and total) content of algal cultures (with different concentrations) were optimized to investigate the power generation performance of each cell. The BEFC cell (ITO/Alg10/Cr3//Carbon) with optimized amounts of Alg and CQDs demonstrated enhanced photocurrent generation of 120 mA cm⁻² at a photo-generated potential of 24.6 V m⁻². The same device exhibited a maximum power density of 7 W m⁻² under continuous light illumination. The device also maintained 98% of its initial performance after 30 repeated cycles of light on–off measurements.