Microbial fuel cells: a green and alternative source for bioenergy production

Microbial fuel cell (MFC) represents one of the green technologies for the production of bioenergy. MFCs using microalgae produce bioenergy by converting solar energy into electrical energy as a function of metabolic and anabolic pathways of the cells. In the MFCs with bacteria, bioenergy is generated as a result of the organic substrate oxidation. MFCs have received high attention from researchers in the last years due to the simplicity of the process, the absence in toxic by-products, and low requirements for the algae growth. Many studies have been conducted on MFC and investigated the factors affecting the MFC performance. In the current chapter, the performance of MFC in producing bioenergy as well as the factors which influence the efficacy of MFCs is discussed. It appears that the main factors affecting MFC’s performance include bacterial and algae species, pH, temperature, salinity, substrate, mechanism of electron transfer in an anodic chamber, electrodes materials, surface area, and electron acceptor in a cathodic chamber. These factors are becoming more influential and might lead to overproduction of bioenergy when they are optimized using response surface methodology (RSM)

Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes

Copyright: © 2010 Stimpson et al.Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extrachromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.This work was supported by the Tumorzentrum Heidelberg/Mannheim grant (D.10026941)and by March of Dimes Research Foundation grant #1-FY06-377 and NIH R01 GM069514

Neural Stem Cells Achieve and Maintain Pluripotency without Feeder Cells

Background: Differentiated cells can be reprogrammed into pluripotency by transduction of four defined transcription factors. Induced pluripotent stem cells (iPS cells) are expected to be useful for regenerative medicine as well as basic research. Recently, the report showed that mouse embryonic fibroblasts (MEF) cells are not essential for reprogramming. However, in using fibroblasts as donor cells for reprogramming, individual fibroblasts that had failed to reprogram could function as feeder cells. Methodology/Principal Finding: Here, we show that adult mouse neural stem cells (NSCs), which are not functional feeder cells, can be reprogrammed into iPS cells using defined four factors (Oct4, Sox2, Klf4, and c-Myc) under feeder-free conditions. The iPS cells, generated from NSCs expressing the Oct4-GFP reporter gene, could proliferate for more than two months (passage 20). Generated and maintained without feeder cells, these iPS cells expressed pluripotency markers (Oct4 and Nanog), the promoter regions of Oct4 and Nanog were hypomethylated, could differentiated into to all three germ layers in vitro, and formed a germline chimera. These data indicate that NSCs can achieve and maintain pluripotency under feeder-free conditions. Conclusion/Significance: This study suggested that factors secreted by feeder cells are not essential in the initial/early stages of reprogramming and for pluripotency maintenance. This technology might be useful for a human system, as

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Chitosan/halloysite beads fabricated by ultrasonic-assisted extrusion-dripping and a case study application for copper ion removal

Development of new materials for different applications especially as bio-composites has received great attention. This study concentrates on development of a biopolymer based on chitosan (CT) and halloysite nanotubes (HNT) and evaluates the copper removal intake as a potential application of this bio-composite. In this study, CT/HNT beads were prepared by ultrasonic-assisted extrusion-dripping method for the first time. Two sources of HNTs (i.e. Dragonite and Matauri Bay) were added into a chitosan solution (2 wt.%) at various loading fractions (25, 50, 75 wt.%). The effect of ultrasound as a mixing device was also studied by varying the amplitude at constant frequency of 25%, 50% and 75%. Characteristics and physical properties of the prepared CT/HNT beads were also analyzed by SEM, FTIR, TGA and BET the results show that introducing HNT to chitosan increases the adsorption capacity toward copper ions; however HNT loading fraction above 50 wt.% resulted in a decrease in adsorption capacity attributed to limited accessibility of the amino groups. The adsorption capacity of the CT/HNT beads prepared from Dragonite source had a larger adsorption capacity of 14.2 mg/g as compared to that of Matauri Bay, 10.55 mg/g. It was observed that the adsorption capacity of the beads toward copper ions decreased when the loading fraction of HNT is increased at constant ultrasound amplitude. The result of this study helps to understand the links between the characteristics and adsorption abilities of CT/HNT beads

Green multi-functional monomer based ion imprinted polymers for selective removal of copper ions from aqueous solution

Green ion imprinted polymers (IIPs) were prepared in aqueous phase via the synergy of three functional monomers of low-cost eco-friendly gelatin (G), 8-hydroxyquinoline (HQ) and chitosan (C), namely G-HQ-C IIPs, and were applied as an effective and recyclable adsorbent to remove Cu(II) from aqueous solution. The as-prepared G-HQ-C IIPs were systematically characterized, and several major factors affecting adsorption capacity including solution pH, temperature and contact time were investigated in detail. The adsorption of Cu(II) on G-HQ-C IIPs followed the pseudo-second-order kinetic and Langmuir isotherm models, and the adsorption capacity increased with temperature increase. Moreover, the maximum adsorption capacities of G-HQ-C IIPs toward Cu(II) reached up to 111.81 mg/g at room temperature, much higher than those of most of the reported adsorbents for Cu(II). The G-HQ-C IIPs displayed excellent selectivity against seven common divalent ions with selectivity coefficients above 18.71, as well as high anti-interference ability. Additionally, a good reusability was demonstrated without significant loss in adsorption capacity after at least ten cycles. The IIPs were applied to environmental water samples for selective removal of Cu(II) with satisfactory results. By replacing Cu(II) template by Cd(II), Hg(II) and Pb(II), respectively, the obtained three kinds of IIPs based on G-HQ-C presented convincing imprinting properties, and therefore the work could provide a simple and general imprinting strategy toward various concerned heavy metal ions through multi-point interactions from multiple functional monomers. (C) 2019 Elsevier Inc. All rights reserved

Efficient deoxygenation of triglycerides to hydrocarbon-biofuel over mesoporous Al<inf>2</inf>O<inf>3</inf>-TiO<inf>2</inf> catalyst

© 2019 Elsevier B.V. The renewable hydrocarbon-like biofuel from biomass is crucial to substitute fossil fuel. A series of mesoporous Al2O3-TiO2 mixed oxide catalysts with different TiO2 content (0.1Ti-0.9Al, 0.2Ti-0.8Al and 0.3Ti-0.7Al) have been synthesized. The physicochemical properties of the catalysts were characterized by XRD, FESEM-EDX, BET, FTIR, NH3-TPD, FTIR-Py, and TGA. The deoxygenation (DO) of triglyceride (i.e. triolein) was carried out in the absence of hydrogen and solvent. The mesoporous Al2O3-TiO2 catalysts showed high catalytic activity performance as compared to that of Al2O3 and TiO2. It was found that 0.2Ti-0.8Al catalyst exhibited the highest conversion (76.86%), and selectivity (27.26%) toward n-C15 + n-C17 at 380 °C after 4 h. The excellence performance of mesoporous Al2O3-TiO2 was attributed to its acidity, mesoporosity and larger surface area. The results reveal that the mesoporous Al2O3-TiO2 catalyst is a promising catalyst for the synthesis of hydrocarbon-like biofuel

Ratiometric fluorescence and colorimetry dual-mode assay based on manganese dioxide nanosheets for visual detection of alkaline phosphatase activity

Alkaline phosphatase (ALP) activity plays a crucial role in foods and varies greatly in livestock and dairy products; it is quite difficult to compatibly monitor the different activities in various complicated foods. Herein, we proposed a ratiometric fluorescence and colorimetry dual-mode assay based on manganese dioxide (MnO2) nanosheets for the visualization of ALP activity in livestock serum and pasteurized milk samples compatibly. MnO2 nanosheets could oxidize dopamine into green fluorescent polydopamine (PDA) nanoparticles, so to quench the red fluorescent quantum dots (QDs), or oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) into yellow TMBox. In the coexistence of ALP and 2-phospho-L-ascorbic acid, MnO2 nanosheets were reduced into Mn2+ ions by the catalysate of ascorbic acid, failing to generate PDA nanoparticles, and therefore, recovering the fluorescence of QDs for ratiometric fluorescence detection of high-activity ALP, or weakening the oxidization of TMB for colorimetric detection of ultralow-activity ALP. The ratiometric fluorescence-colorimetry combination extended the linear range over three orders of magnitude (0.04-80 mU/mL), and lowered the detection limit down to 0.015 mU/mL, along with profuse ALP-dependent (fluorescence) color changes for visual detection of ALP activity. Excellent recognition selectivity for ALP was attained over possibly coexistent reducing substances. Furthermore, the endogenous ALP were detected ranging from 17.32 to 269.54 mU/mL in seven typical livestock sera, consistent with that measured by commercial ALP assay kit; the detection results for ALP in four pasteurized milks matched well with that by test paper. The developed dual-mode assay held great potential for rapid on-site visual determination of reductant-related analytes in complicated matrices