Removal of Acid Yellow 25 from Aqueous Solution by Chitin Prepared from Waste Snow Crab Legs

Acid Yellow 25 (AY25) is used in the textile industry for dyeing of natural and synthetic fibers, and is also used as a coloring agent in paints, inks, plastics, and leathers. Effluents from such industries are major sources of water pollution. Hence, it is important to find simple, efficient, and inexpensive ways to remove these dyes from wastewater. Here, we determined the suitability of chitin extracted from waste crab legs as an adsorbent for removing AY25 dye. The adsorption kinetics was modeled using pseudo-first order, pseudo-second order, and intraparticle diffusion equations to determine the rate controlling step. Results showed that the pseudo-second order adsorption mechanism is predominant, and the overall rate of the dye adsorption process is therefore controlled by an adsorption reaction. Adsorption isotherms were analyzed by utilizing the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models at 23˚C, with data collected by using various initial dye concentrations with different chitin dosages. Our results show the highest correlation with the Langmuir model, consistent with the fact that chitin contains both a monolayer and homogeneous adsorption sites. Based on the D-R model, the adsorption of AY25 dye onto chitin is via chemisorption. Furthermore, we have concluded that the rate constants of both pseudo-second order adsorption and film diffusion are correlated to the initial dye concentrations and chitin dosages. In conclusion, chitin from waste crab legs is a very suitable adsorbent material that is capable of rapidly removing up to 95% of the initial concentration of AY25 dye at a pH of 2 and room temperature

Maternally inherited piRNAs direct transient heterochromatin formation at active transposons during early Drosophila embryogenesis

The PIWI-interacting RNA (piRNA) pathway controls transposon expression in animal germ cells, thereby ensuring genome stability over generations. In Drosophila, piRNAs are intergenerationally inherited through the maternal lineage, and this has demonstrated importance in the specification of piRNA source loci and in silencing of I- and P-elements in the germ cells of daughters. Maternally inherited Piwi protein enters somatic nuclei in early embryos prior to zygotic genome activation and persists therein for roughly half of the time required to complete embryonic development. To investigate the role of the piRNA pathway in the embryonic soma, we created a conditionally unstable Piwi protein. This enabled maternally deposited Piwi to be cleared from newly laid embryos within 30 min and well ahead of the activation of zygotic transcription. Examination of RNA and protein profiles over time, and correlation with patterns of H3K9me3 deposition, suggests a role for maternally deposited Piwi in attenuating zygotic transposon expression in somatic cells of the developing embryo. In particular, robust deposition of piRNAs targeting roo, an element whose expression is mainly restricted to embryonic development, results in the deposition of transient heterochromatic marks at active roo insertions. We hypothesize that roo, an extremely successful mobile element, may have adopted a lifestyle of expression in the embryonic soma to evade silencing in germ cells

High-Frequency Dynamics of Ocean pH: A Multi-Ecosystem Comparison

The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO2, reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a compilation of continuous, high-resolution time series of upper ocean pH, collected using autonomous sensors, over a variety of ecosystems ranging from polar to tropical, open-ocean to coastal, kelp forest to coral reef. These observations reveal a continuum of month-long pH variability with standard deviations from 0.004 to 0.277 and ranges spanning 0.024 to 1.430 pH units. The nature of the observed variability was also highly site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of varying amplitudes. These biome-specific pH signatures disclose current levels of exposure to both high and low dissolved CO2, often demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100. Our data provide a first step toward crystallizing the biophysical link between environmental history of pH exposure and physiological resilience of marine organisms to fluctuations in seawater CO2. Knowledge of this spatial and temporal variation in seawater chemistry allows us to improve the design of OA experiments: we can test organisms with a priori expectations of their tolerance guardrails, based on their natural range of exposure. Such hypothesis-testing will provide a deeper understanding of the effects of OA. Both intuitively simple to understand and powerfully informative, these and similar comparative time series can help guide management efforts to identify areas of marine habitat that can serve as refugia to acidification as well as areas that are particularly vulnerable to future ocean change

Characterization of the EF-Hand Domains of NADPH Oxidase 5

Reactive oxygen species (ROS) are a class of oxygen compounds that are highly reactive due to their partially reduced oxygen atom, with examples including superoxide (O2-), hydrogen peroxide (H2O2), and peroxide (O2-2). ROS play a critical role in the body with their involvement in cell signaling and host cell defense when proper levels are maintained. The production of the ROS superoxide in particular is largely facilitated by the enzyme family of NADPH oxidases (Noxs). Production of the superoxide via the Nox enzyme family has been shown to play a role in the regulation of homeostasis conditions in the body. However, overproduction or underproduction can lead to disease development or trouble combating pathogens, respectively. Two homologs of the Nox family, NADPH Oxidase 5 (Nox5) and Dual oxidase (Duox), contain an additional EF-Hand Domain (EFD) that requires Ca2+ coordination to its EF-Hand motifs to stimulate superoxide production. Binding of Ca2+ to the EFD stimulates a conformational change that involves the exposure of hydrophobic amino acid residues. Previous studies have suggested that the hydrophobic residue exposure prompts the interaction of the EFD with the dehydrogenase domain (DH) within the same enzyme. However, the exact structure of the EFD as well as the conformational change remain unknown. To elucidate the structure of Nox5-EFD and the conformational change that occurs upon Ca2+ coordination, recombinant protein constructs for the Nox5 EFD were expressed and purified. The Ca2+ binding assessed by isothermal titration calorimetry (ITC) revealed that the binding constant of Ca2+ is much higher in the third EF of Nox5 (108 M-1) than in the other EF motifs. Assessment of cooperativity showed that the C-terminal of Nox5-EFD (C-EFD) exhibits cooperativity to the order of 14000, where N-EFD has a lower cooperativity of 1500, likely attributed to the high affinity of EF3 and the low affinity of EF1. Assessment of hydrophobicity by the ANS interaction with Nox5-EFD suggested that the most significant hydrophobic exposure occurs in a portion of the C-terminal linker region and a portion of the C-terminal lobe, complementary to the findings from the determination of heat capacity (ΔCp) for Nox5-EFD. The limited trypsin digestion revealed burial of the polar Lys and Arg residues in the C-terminus, leading to digestion resistance in the 10 kDa digestion fragment. The potential use of CaM as a model protein for Nox5-EFD is discussed

Mapping WPI Alumni Career Trajectories Through Data Visualization

It is a constant challenge for academic institutions to keep up with the transforming economy as workplaces change and new types of careers and opportunities become available. This project aims to create a data visualization tool that enables exploration of WPI’s Foisie Business School alumni career trajectories and students’ academic pursuits. In this project, we develop a comprehensive anonymized alumni career trajectory database and a WPI alumni career trajectory data visualization tool. This tool will act as a resource for WPI students interested in mapping their potential careers and provide a comprehensive understanding of alumni career paths after college and how undergraduate decisions affect those paths

Further investigation of phenotypes and confounding factors of progressive ratio performance and feeding behavior in the BACHD rat model of Huntington disease.

Huntington disease is an inherited neurodegenerative disorder characterized by motor, cognitive, psychiatric and metabolic symptoms. We recently published a study describing that the BACHD rat model of HD shows an obesity phenotype, which might affect their motivation to perform food-based behavioral tests. Further, we argued that using a food restriction protocol based on matching BACHD and wild type rats' food consumption rates might resolve these motivational differences. In the current study, we followed up on these ideas in a longitudinal study of the rats' performance in a progressive ratio test. We also investigated the phenotype of reduced food consumption rate, which is typically seen in food-restricted BACHD rats, in greater detail. In line with our previous study, the BACHD rats were less motivated to perform the progressive ratio test compared to their wild type littermates, although the phenotype was no longer present when the rats' food consumption rates had been matched. However, video analysis of food consumption tests suggested that the reduced consumption rate found in the BACHD rats was not entirely based on differences in hunger, but likely involved motoric impairments. Thus, restriction protocols based on food consumption rates are not appropriate when working with BACHD rats. As an alternative, we suggest that studies where BACHD rats are used should investigate how the readouts of interest are affected by motivational differences, and use appropriate control tests to avoid misleading results. In addition, we show that BACHD rats display distinct behavioral changes in their progressive ratio performance, which might be indicative of striatal dysfunction

Correction: Further investigation of phenotypes and confounding factors of progressive ratio performance and feeding behavior in the BACHD rat model of Huntington disease.

[This corrects the article DOI: 10.1371/journal.pone.0173232.]