Extraction of chitin from edible crab shells of Callinectes sapidus and comparison with market purchased chitin

Chitin and its derived products have immense economic value due to their vital role in various biological activities as well as biomedical and industrial application. Insects, microorganism and crustaceans are the main supply of chitin but the crustaceans shell like shrimp, krill, lobsters and crabs are the main commercial sources. Chitin content of an individual varies depending on the structures possessing the polymer and the species. In this study edible crabs’ shells (Callinectes sapidus) were demineralized and deproteinized resulting in 13.8% (dry weight) chitin recovery from chitin wastes. FTIR and XRD analyses of the experimental crude as well as purified chitins revealed that both were much comparable to the commercially purchased controls. The acid pretreatment ceded 54g of colloidal chitin that resulted in 1080% of the crude chitin. The colloidal chitin was exploited for isolation of eighty five chitinolytic bacterial isolates from different sources. Zone of clearance was displayed by the thirty five isolates (41.17%) succeeding their growth at pH 7 on colloidal chitin agar medium. Maximum chitinolytic activity i.e. 301.55 U/ml was exhibited by isolate JF70 when cultivated in extracted chitin containing both carbon and nitrogen. The study showed wastes of blue crabs can be utilized for extraction of chitin and isolation of chitinolytic bacteria that can be used to degrade chitin waste, resolve environmental pollution as well as industrial purpose.

Generation and diversification of recombinant monoclonal antibodies

Antibodies are indispensable tools used for a large number of applications in both foundational and translational bioscience research; however, there are drawbacks to using traditional antibodies generated in animals. These include a lack of standardization leading to problems with reproducibility, high costs of antibodies purchased from commercial sources, and ethical concerns regarding the large number of animals used to generate antibodies. To address these issues, we have developed practical methodologies and tools for generating low-cost, high-yield preparations of recombinant monoclonal antibodies and antibody fragments directed to protein epitopes from primary sequences. We describe these methods here, as well as approaches to diversify monoclonal antibodies, including customization of antibody species specificity, generation of genetically encoded small antibody fragments, and conversion of single chain antibody fragments (e.g. scFv) into full-length, bivalent antibodies. This study focuses on antibodies directed to epitopes important for mitosis and kinetochore function; however, the methods and reagents described here are applicable to antibodies and antibody fragments for use in any field.

The DNMT1 inhibitor GSK-3484862 mediates global demethylation in murine embryonic stem cells

Background DNA methylation plays an important role in regulating gene expression in mammals. The covalent DNMT1 inhibitors 5-azacytidine and decitabine are widely used in research to reduce DNA methylation levels, but they impart severe cytotoxicity which limits their demethylation capability and confounds interpretation of experiments. Recently, a non-covalent inhibitor of DNMT1 called GSK-3484862 was developed by GlaxoSmithKline. We sought to determine whether GSK-3484862 can induce demethylation more effectively than 5-azanucleosides. Murine embryonic stem cells (mESCs) are an ideal cell type in which to conduct such experiments, as they have a high degree of DNA methylation but tolerate dramatic methylation loss. Results We determined the cytotoxicity and optimal concentration of GSK-3484862 by treating wild-type (WT) or Dnmt1/3a/3b triple knockout (TKO) mESC with different concentrations of the compound, which was obtained from two commercial sources. Concentrations of 10 µM or below were readily tolerated for 14 days of culture. Known DNA methylation targets such as germline genes and GLN-family transposons were upregulated within 2 days of the start of GSK-3484862 treatment. By contrast, 5-azacytidine and decitabine induced weaker upregulation of methylated genes and extensive cell death. Whole-genome bisulfite sequencing showed that treatment with GSK-3484862 induced dramatic DNA methylation loss, with global CpG methylation levels falling from near 70% in WT mESC to less than 18% after 6 days of treatment with GSK-3484862. The treated cells showed a methylation level and pattern similar to that observed in Dnmt1-deficient mESCs. Conclusions GSK-3484862 mediates striking demethylation in mESCs with minimal non-specific toxicity.

Evaluation of Phosphorus Digestibility from Monocalcium and Dicalcium Phosphate Sources and Comparison between Total Tract and Prececal Digestibility Standard Methods in Broilers

The objective of this study was to compare the total tract (total excreta and marker) and prececal methodologies to determine phosphorus (P) digestibility and to evaluate its variation as a function of the physicochemical characteristics of the inorganic phosphate used (monocalcium, MCP and dicalcium, DCP) from different commercial sources. A total of 176 1-day-old male broilers were used in two digestibility experiments. In Experiment 1, one MCP and one DCP were incorporated in the basal diet at two levels. In Experiment 2, MCP and DCP from three commercial sources were incorporated to the basal diet at one level. Physicochemical characteristics of inorganic phosphates were examined, as well. Additionally, bone mineralization and growth performance traits were investigated in both trials. The digestibility of MCP ranged from 75.2 to 87.4% and from 80.5 to 86.6% for DCP amongst methodologies, but differences between total tract and preceal methodologies were not statistically significant. Particle size, surface area, degree of crystallinity and impurities varied amongst commercial sources. The P digestibility of the three tested commercial sources of MCP was 79.6% (MCP1), 70.2% (MCP2) and 65.6% (MCP3); p > 0.05. The P digestibility of the 3 tested commercial sources of DCP was 80.1% (DCP1), 77.4% (DCP2) and 71.4% (DCP3); p > 0.05.

ChemSkin Reference Chemical Database for the Development of an In Vitro Skin Irritation Test

Since the animal test ban on cosmetics in the EU in 2013, alternative in vitro safety tests have been actively researched to replace in vivo animal tests. For the development and evaluation of a new test method, reference chemicals with quality in vivo data are essential to assess the predictive capacity and applicability domain. Here, we compiled a reference chemical database (ChemSkin DB) for the development and evaluation of new in vitro skin irritation tests. The first candidates were selected from 317 chemicals (source data n = 1567) searched from the literature from the last 20 years, including previous validation study reports, ECETOC, and published papers. Chemicals showing inconsistent classification or those that were commercially unavailable, difficult or dangerous to handle, prohibitively expensive, or without quality in vivo or in vitro data were removed, leaving a total of 100 chemicals. Supporting references, in vivo Draize scores, UN GHS/EU CLP classifications and commercial sources were compiled. Test results produced by the approved methods of OECD Test No. 439 were included and compared using the classification table, scatter plot, and Pearson correlation analysis to identify the false predictions and differences between in vitro skin irritation tests. These results may provide an insight into the future development of new in vitro skin irritation tests.

Microplastic Abundance in Blood Cockles and Shrimps from Fishery Market, Songkhla Province, Southern Thailand

Microplastics have been one of the major pollutants in the marine environment throughout the recent decade. At present, microplastic contamination in marine ecosystems of Thailand region has become an increasing environmental concern because the ingestion of microplastics in marine organisms may adversely influence the safety of seafood. Cockles and shrimps widely distribute among marine organisms in Thailand since they are one of the commercial sources of seafood, which may be a route of exposure to microplastics towards human. This study documents a market survey in order to understand the extension of microplastic presence in blood cockles (Anadara granosa), fine shrimp (Metapenaeus elegans) and Indian white shrimp (Fenneropenaeus indicus) sold in the fishery market in Singhanakorn district, Songkhla province. These selected species are widely consumed and economically important, especially in the southern Thailand region. The total microplastic concentration in blood cockles is 4.71±0.06 n/g (wet weight) and 2.64±0.01 n/individual; in fine shrimp is 0.50±0.19 n/g (wet weight) and 3.70±1.12 n/individual; in Indian white shrimp is 0.69±0.48 n/g (wet weight) and 3.45±0.04n/individual. Discovered microplastics in all the species samples were mainly composed of microplastic fibres and black colour was found to be more predominant. Our results indicate that microplastic contamination is present in Thailand’s commercial seafood species. As microplastic able to be transferred to human through food web, we suggest further market-based survey studies on other seafood sources.

Mod3D: A Low-Cost, Flexible Modular System of Live-Cell Microscopy Chambers and Holders

Live-cell microscopy imaging typically involves the use of high-quality glass-bottom chambers that allow cell culture, gaseous buffer exchange and optical properties suitable for microscopy applications. However, commercial sources of these chambers can add significant annual costs to cell biology laboratories. Consumer products in three-dimensional printing technology, for both Filament Deposition Modeling (FDM) and Masked Stereo Lithography (MSLA), have resulted in more biomedical research labs adopting the use of these devices for prototyping and manufacturing of lab plastic-based items, but rarely consumables. Here we describe a modular, live-cell chamber with multiple design options that can be mixed per experiment. Single reusable carriers and the use of biodegradable plastics, in a hybrid of FDM and MSLA manufacturing methods, reduce plastic waste. The system is easy to adapt to bespoke designs, with concept-to-prototype in a single day, offers significant cost savings to the users over commercial sources, and no loss in dimensional quality or reliability.

“You Do It Through the Grapevine”: A Bourdieusian Analysis of Under-Age Access to Tobacco Among Adolescents From Seven European Cities

Despite efforts to reduce adolescent smoking via minimum age-of-sale legislation, many young people continue to access tobacco through a mix of social and commercial sources. Little is known about the roles of habitus, capital, and social topographies in shaping under-age access to tobacco. This article draws on Bourdieu’s theory of practice and data generated from 56 focus groups with 14- to 19-year-olds across seven European cities to answer the question “via what sources and by what means do adolescents obtain tobacco?” We find that adolescents use a range of personal capitals (social, cultural, and economic) to access tobacco, with the specific constitution and deployment of these capitals varying according to the regularities of different fields. Since adolescents access tobacco via culturally embedded practices, attempts to curtail this access are more likely to be effective if they are multi-pronged, culturally informed, and attuned to the lived experiences of adolescent smokers.

Content analysis and reliability of YouTube™ videos on clear aligner

Objectives: The aim of the present study is to evaluate the accuracy and reliability of the information provided in the videos about the clear aligner on the Youtube video platform, an internet information source. Materials and Methods: A video search was performed on the Youtube video platform using three keywords determined with the Google Trends application. After the videos were ranked based on their view counts, a total of 75 videos were analyzed, 47 being the first for each term. After applying the exclusion criteria (repetitive content, no audio content or title information, irrelevant to the topic, only promotional content, duration over 15 min, and addressing other orthodontic treatments), the remaining 47 videos were evaluated. Regarding the videos, the following parameters were recorded: View count, number of likes, number of dislikes, number of comments, video duration, and days since the uploaded date. A scoring system consisting of seven parameters was used to classify the video content quality as low and high. The video information and quality index were utilized to evaluate the quality of the videos universally. Statistical analyses were performed with Stata/IC computer program using Shapiro–Wilks, Kruskall–Wallis, Mann–Whitney U, and linear regression (Backward method) tests. Statistical significance value was set at P < 0.05. Results: Evaluation of the videos based on their upload source revealed that 27 videos were downloaded from individuals, ten videos from doctors and ten videos from commercial sources, and the number of subscribers to these sources varied significantly (P < 0.05). Evaluation of the videos based on the information provided, revealed that 32 videos had poor quality, ten videos had moderate quality and five videos had good quality information content, and the video durations varied significantly (P < 0.05). It was seen that of the 75 videos viewed, only 10 (13.3%) provided information of moderate-good quality. The number of likes was found to be the parameter that significantly affects the view count (P < 0.05). Conclusion: YouTube videos prove insufficient as a source of information on orthodontic treatment with clear aligner. Health-care professionals should be aware of online platforms to ensure that patients can access accurate information.