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Production engineering

Vahid Mirshafiee, Bingbing Sun, Chong Hyun Chang, Yu-Pei Liao, Wen Jiang, Jinhong Jiang, Xiangsheng Liu, Xiang Wang, Tian Xia, Andre E Nel
The liver and the mononuclear phagocyte system (MPS) is a frequent target for engineered nanomaterials (ENMs), either as a result of particle uptake and spread from primary exposure sites or systemic administration of therapeutic and imaging nanoparticles. In this study, we performed a comparative analysis of the toxicological impact of 29 metal oxide (MOx) nanoparticles (NPs), some commonly used in consumer products, in transformed or primary Kupffer cells (KCs) and hepatocytes. Not only did we observe differences between KC and hepatocytes, but also differences in the toxicological profiles of transition metal oxides (TMOs, e...
March 15, 2018: ACS Nano
Katherine D Hills, Daniela A Oliveira, Nicholas D Cavallaro, Carmen L Gomes, Eric S McLamore
We demonstrate a sensing mechanism for rapid detection of Listeria monocytogenes in food samples using the actuation of chitosan-aptamer nanobrush borders. The bio-inspired soft material and sensing strategy mimic natural symbiotic systems, where low levels of bacteria are selectively captured from complex matrices. To engineer this biomimetic system, we first develop reduced graphene oxide/nanoplatinum (rGO-nPt) electrodes, and characterize the fundamental electrochemical behavior in the presence and absence of chitosan nanobrushes during actuation (pH-stimulated osmotic swelling)...
March 15, 2018: Analyst
María Huete-Ortega, Katarzyna Okurowska, Rahul Vijay Kapoore, Matthew P Johnson, D James Gilmour, Seetharaman Vaidyanathan
Background: Microalgae accumulate lipids when exposed to stressful conditions such as nutrient limitation that can be used to generate biofuels. Nitrogen limitation or deprivation is a strategy widely employed to elicit this response. However, this strategy is associated with a reduction in the microalgal growth, leading to overall poor lipid productivities. Here, we investigated the combined effect of a reduced source of nitrogen (ammonium) and super-saturating light intensities on the growth and induction of lipid accumulation in two model but diverse microalgal species, Phaeodactylum tricornutum and Nannochloropsis oceanica ...
2018: Biotechnology for Biofuels
Wenlong Zhou, Yan Yang, Liang Tang, Kai Cheng, Changkun Li, Huimin Wang, Minzhi Liu, Wei Wang
Acrolein (Acr) was used as a selection agent to improve the glutathione (GSH) overproduction of the prototrophic strain W303-1b/FGPPT . After two rounds of adaptive laboratory evolution (ALE), an unexpected result was obtained wherein identical GSH production was observed in the selected isolates. Then, a threshold selection mechanism of Acr-stressed adaption was clarified based on the formation of an Acr-GSH adduct, and a diffusion coefficient (0.36 ± 0.02 μmol·min-1 ·OD600 -1 ) was calculated. Metabolomic analysis was carried out to reveal the molecular bases that triggered GSH overproduction...
March 14, 2018: Scientific Reports
Robert J Miller, Kevin D Lafferty, Thomas Lamy, Li Kui, Andrew Rassweiler, Daniel C Reed
Foundation species define the ecosystems they live in, but ecologists have often characterized dominant plants as foundational without supporting evidence. Giant kelp has long been considered a marine foundation species due to its complex structure and high productivity; however, there is little quantitative evidence to evaluate this. Here, we apply structural equation modelling to a 15-year time series of reef community data to evaluate how giant kelp affects the reef community. Although species richness was positively associated with giant kelp biomass, most direct paths did not involve giant kelp...
March 14, 2018: Proceedings. Biological Sciences
Sopita Wongin, Saranatra Waikakul, Pojchong Chotiyarnwong, Wanwipa Siriwatwechakul, Masahiro Kino-Oka, Mee-Hae Kim, Kwanchanok Viravaidya-Pasuwat
BACKGROUND: Dedifferentiation of chondrocytes during cell expansion is one of the barriers in tissue construction for cartilage repair. To understand chondrocyte behavior and improve cell expansion in monolayer culture, this study investigated the effects of morphological changes and cellular aggregation on the maintenance of chondrogenic capacity by observing the expression patterns of chondrogenic (collagen type II and aggrecan) and dedifferentiation (collagen type I) markers. Primary human chondrocytes were cultured on either a polystyrene surface (PS) or a polyamidoamine dendrimer surface with a fifth-generation (G5) dendron structure to create a one-step process of cell expansion and the maintenance of chondrogenic activities prior to the construction of cell sheets...
March 14, 2018: BMC Biotechnology
M Cheetham, A Wiseman, B Khazaeli, E Gibson, P Gray, P Van der Graaf, R Rushmer
Background: Embedded research (ER) is recognized as one way to strengthen the integration of evidence into public health (PH) practice. In this paper, we outline a promising example of the co-production of research evidence between Fuse, the UKCRC Centre for Translational Research in Public Health and a local authority (LA) in north east England. Methods: We critically examine attempts to share and use research findings to influence decision-making in a LA setting, drawing on insights from PH practitioners, managers, commissioners and academic partners involved in this organizational case study...
March 1, 2018: Journal of Public Health
James C Courtenay, Ram I Sharma, Janet L Scott
Tissue engineering is a rapidly advancing field in regenerative medicine, with much research directed towards the production of new biomaterial scaffolds with tailored properties to generate functional tissue for specific applications. Recently, principles of sustainability, eco-efficiency and green chemistry have begun to guide the development of a new generation of materials, such as cellulose, as an alternative to conventional polymers based on conversion of fossil carbon (e.g., oil) and finding technologies to reduce the use of animal and human derived biomolecules (e...
March 14, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Chandran Sathesh-Prabu, Sung Kuk Lee
The production of α,ω-dicarboxylic acids (DCAs) by whole-cell biocatalysis is often limited by cofactor regeneration. Here, ω-oxidation pathway genes (monooxygenase, alcohol dehydrogenase, and aldehyde dehydrogenase) were co-expressed with a xylose reductase (XR) gene to regenerate cofactors in an engineered Escherichia coli strain that co-metabolizes glucose and xylose. The resulting strain exhibited a 180% increase in DCA production compared with the control strain without XR, and produced xylitol in the presence of xylose...
March 14, 2018: Journal of Agricultural and Food Chemistry
Katia Tarasava, Rongming Liu, Andrew Garst, Ryan T Gill
Optimization of metabolic flux is a difficult and time-consuming process that often involves changing the expression levels of multiple genes simultaneously. While some pathways have a known rate limiting step, more complex metabolic networks can require a trial-and-error approach of tuning the expression of multiple genes to achieve a desired distribution of metabolic resources. Here we present an efficient method for generating expression diversity on a combinatorial scale using CRISPR interference. We use a modified native Escherichia coli Type I-E CRISPR-Cas system and an iterative cloning strategy for construction of guide RNA arrays...
March 14, 2018: Biotechnology and Bioengineering
Wei Xiong, Luis H Reyes, William E Michener, Pin-Ching Maness, Katherine J Chou
Cellulose and hemicellulose are the most abundant components in plant biomass. A preferred Consolidated Bioprocessing (CBP) system is one which can directly convert both cellulose and hemicellulose into target products without adding the costly hydrolytic enzyme cocktail. In this work, the thermophilic, cellulolytic, and anaerobic bacterium, Clostridium thermocellum DSM 1313, was engineered to grow on xylose in addition to cellulose. Both xylA (encoding for xylose isomerase) and xylB (encoding for xylulokinase) genes from the thermophilic anaerobic bacterium Thermoanaerobacter ethanolicus were introduced to enable xylose utilization while still retaining its inherent ability to grow on 6-carbon substrates...
March 14, 2018: Biotechnology and Bioengineering
Ramkumar T Annamalai, Tapan Girish Naik, Haley Prout, Andrew J Putnam, Jan P Stegemann
Microtissues created from the protein fibrin and containing embedded cells can be used in modular tissue engineering approaches to create larger, hierarchical and complex tissue structures. In this paper we demonstrate an emulsification-based method for the production of such fibrin microtissues containing fibroblasts and endothelial cells and designed to promote tissue vascularization. Surfactants can be beneficial in the microtissue fabrication process to reduce aggregation and to facilitate recovery of microtissues from the emulsion, thereby increasing yield...
March 14, 2018: Biomedical Materials
Zheng-Zhe Zhang, Ya-Fei Cheng, Lian-Zeng-Ji Xu, Yu-Hui Bai, Ren-Cun Jin
The increasing use of engineered Ag nanoparticles (NPs) in consumer products raises great concerns about their environmental impacts, but their potential impact on anaerobic ammonium oxidation (anammox) bacteria in wastewater treatment remains unclear. In this study, the response of anammox consortia inhabiting in granules to long-term exposure of AgNPs was investigated. The gradually increased stress of AgNPs (1, 10, 50 mg L-1 ) showed no adverse effects on the nitrogen removal performance and on the relative abundance of Ca...
March 7, 2018: Bioresource Technology
Yuan Li, Wan Zhang, Hui Zhang, Wenya Tian, Lian Wu, Shuwen Wang, Mengmeng Zheng, Jinru Zhang, Chenghai Sun, Zixin Deng, Yuhui Sun, Xudong Qu, Jiahai Zhou
Polyketides are a large family of pharmaceutically important natural products, and the structural modification of their scaffolds is significant for drug development. Herein, we report one apo- and two complex structures (with a pentynylmalonyl and benzylmalonyl, respectively) of the broadly selective acyltransferase (AT) from the splenocin polyketide synthase. These structures revealed the molecular basis of the stereo-selectivity and substrate specificity of SpnD-AT and enabled engineering the industrially important Ery-AT6 to broaden its substrate scope to include three new types of extender units...
March 14, 2018: Angewandte Chemie
Peng Zhang, Xing Hu
Urea is an important precursor of the harmful carcinogenic product ethyl carbamate in fermented wines. To decipher more fully the contributions of three arginine permeases, Can1p, Gap1p and Alp1p in urea formation, various engineered strains were examined for their ability to form urea. This included seven mutants with different combinations of permease deficiency and grown in both simple and more complex media, and the wild-type strain modified to overexpress the three arginine permeases. A truncated GATA transcription factor, Gln3p1-653 , was also overexpressed in the arginine permease deficient mutants to determine whether the permeases have a synergistic effect on urea formation with other urea reducing modules...
March 13, 2018: World Journal of Microbiology & Biotechnology
Dionysios C Watson, Bryant C Yung, Cristina Bergamaschi, Bhabadeb Chowdhury, Jenifer Bear, Dimitris Stellas, Aizea Morales-Kastresana, Jennifer C Jones, Barbara K Felber, Xiaoyuan Chen, George N Pavlakis
The development of extracellular vesicles (EV) for therapeutic applications is contingent upon the establishment of reproducible, scalable, and high-throughput methods for the production and purification of clinical grade EV. Methods including ultracentrifugation (U/C), ultrafiltration, immunoprecipitation, and size-exclusion chromatography (SEC) have been employed to isolate EV, each facing limitations such as efficiency, particle purity, lengthy processing time, and/or sample volume. We developed a cGMP-compatible method for the scalable production, concentration, and isolation of EV through a strategy involving bioreactor culture, tangential flow filtration (TFF), and preparative SEC...
2018: Journal of Extracellular Vesicles
Melissa Lo Monaco, Greet Merckx, Jessica Ratajczak, Pascal Gervois, Petra Hilkens, Peter Clegg, Annelies Bronckaers, Jean-Michel Vandeweerd, Ivo Lambrichts
Due to the restricted intrinsic capacity of resident chondrocytes to regenerate the lost cartilage postinjury, stem cell-based therapies have been proposed as a novel therapeutic approach for cartilage repair. Moreover, stem cell-based therapies using mesenchymal stem cells (MSCs) or induced pluripotent stem cells (iPSCs) have been used successfully in preclinical and clinical settings. Despite these promising reports, the exact mechanisms underlying stem cell-mediated cartilage repair remain uncertain. Stem cells can contribute to cartilage repair via chondrogenic differentiation, via immunomodulation, or by the production of paracrine factors and extracellular vesicles...
2018: Stem Cells International
Heiko Lemcke, Natalia Voronina, Gustav Steinhoff, Robert David
During the past decades, stem cell-based therapy has acquired a promising role in regenerative medicine. The application of novel cell therapeutics for the treatment of cardiovascular diseases could potentially achieve the ambitious aim of effective cardiac regeneration. Despite the highly positive results from preclinical studies, data from phase I/II clinical trials are inconsistent and the improvement of cardiac remodeling and heart performance was found to be quite limited. The major issues which cardiac stem cell therapy is facing include inefficient cell delivery to the site of injury, accompanied by low cell retention and weak effectiveness of remaining stem cells in tissue regeneration...
2018: Stem Cells International
Aleksandra Małachowska, Paweł Olszewski
BACKGROUND: Transcriptional control of gene expression is a widely utilized regulatory mechanism in synthetic biology, biotechnology and recombinant protein production. It is achieved by utilization of naturally occurring promoters responding to nutrients or chemicals. Despite their regulatory properties, these promoters often possess features which diminish their utility for biotechnology. High basal expression level and low induction ratio can be removed using genetic engineering techniques, although this process is often laborious and time-consuming...
March 13, 2018: Microbial Cell Factories
Suresh Neethirajan, Vasanth Ragavan, Xuan Weng, Rohit Chand
Current food production faces tremendous challenges from growing human population, maintaining clean resources and food qualities, and protecting climate and environment. Food sustainability is mostly a cooperative effort resulting in technology development supported by both governments and enterprises. Multiple attempts have been promoted in tackling challenges and enhancing drivers in food production. Biosensors and biosensing technologies with their applications, are being widely applied to tackling top challenges in food production and its sustainability...
March 12, 2018: Biosensors
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