Opportunities for Energy Demand and Carbon Emissions Reduction in the Chemicals Sector

The opportunities and challenges to reducing industrial energy demand and carbon dioxide (CO2) emissions in the Chemicals sector are evaluated with a focus is on the situation in the United Kingdom (UK), although the lessons learned are applicable across much of the industrialised world. This sector can be characterised as being quite heterogeneous, and as sitting on the boundary between energy-intensive (EI) and non-energy-intensive (NEI) industrial sectors. Currently-available technologies will lead to further, short-term energy and CO2 emissions savings in chemicals processing, but the prospects for the commercial exploitation of innovative technologies by mid-21st century are far more speculative. The chemicals sector has long been the largest owner of generating plant in UK industry. Most generation is from CHP plant with significant amounts of excess electricity exported to the grid or other industrial sectors. Special care was taken not to ‘double count’ auto-generation and grid decarbonisation; so that the relative contributions to decarbonisations of each was accounted for separately. There are a number of non-technological barriers to the take-up of such technologies going forward. Consequently, the transition to a low carbon future in UK industry by 2050 will exhibit rather large uncertainties. The attainment of significant falls in carbon emissions over this period will depends critically on the adoption of a small number of key technologies [e.g., carbon capture and storage (CCS), energy efficiency techniques, and bioenergy], alongside a decarbonisation of the electricity supply

Novel Form of Fibronectin from Zebrafish Mediates Infectious Hematopoietic Necrosis Virus Infection

The presence of a novel form of zebrafish fibronectin (FN2) on the cell surface increased the cell’s susceptibility to infection by infectious hematopoietic necrosis virus (IHNV). Unlike other fibronectins, FN2 possesses a truncated structure and accumulates on the cell surface instead of in the extracellular matrix. Fish embryo cells expressing recombinant FN2 were more susceptible to IHNV infection, with a greater percentage of cells exhibiting cytopathic effect (CPE) compared to nontransfected control cells. Incubation of nontransfected cells with soluble recombinant FN2 increased IHNV infection, as measured by plaque assay. The number of plaques increased in correlation with the amount of protein added and the length of time that cells were incubated with the protein. Incubation of IHNV with soluble FN2 before addition to cells also increased infection. FN2 immobilized on the culture surface inhibited IHNV infection. The results indicate that FN2 present on the cell surface is able to mediate IHNV attachment and cell entry

Inducible Sterilization of Zebrafish by Disruption of Primordial Germ Cell Migration.

During zebrafish development, a gradient of stromal-derived factor 1a (Sdf1a) provides the directional cue that guides the migration of the primordial germ cells (PGCs) to the gonadal tissue. Here we describe a method to produce large numbers of infertile fish by inducing ubiquitous expression of Sdf1a in zebrafish embryos resulting in disruption of the normal PGC migration pattern. A transgenic line of zebrafish, Tg(hsp70:sdf1a-nanos3, EGFP), was generated that expresses Sdf1a under the control of the heat-shock protein 70 (hsp70) promoter and nanos3 3?UTR. To better visualize the PGCs, the Tg(hsp70:sdf1a-nanos3, EGFP) fish were crossed with another transgenic line, Tg(kop:DsRed-nanos3), that expresses DsRed driven by the PGC-specific kop promoter. Heat treatment of the transgenic embryos caused an induction of Sdf1a expression throughout the embryo resulting in the disruption of their normal migration. Optimal embryo survival and disruption of PGC migration was achieved when transgenic embryos at the 4- to 8-cell stage were incubated at 34.5°C for 18 hours. Under these conditions, disruption of PGC migration was observed in 100% of the embryos. Sixty-four adult fish were developed from three separate batches of heat-treated embryos and all were found to be infertile males. When each male was paired with a wild-type female, only unfertilized eggs were produced and histological examination revealed that each of the adult male fish possessed severely under-developed gonads that lacked gametes. The results demonstrate that inducible Sdf1a expression is an efficient and reliable strategy to produce infertile fish. This approach makes it convenient to generate large numbers of infertile adult fish while also providing the capability to maintain a fertile brood stock

Dorsomorphin promotes survival and germline competence of zebrafish spermatogonial stem cells in culture.

Zebrafish spermatogonial cell cultures were established from Tg(piwil1:neo);Tg(piwil1:DsRed) transgenic fish using a zebrafish ovarian feeder cell line (OFC3) that was engineered to express zebrafish Lif, Fgf2 and Gdnf. Primary cultures, initiated from testes, were treated with G418 to eliminate the somatic cells and select for the piwil1:neo expressing spermatogonia. Addition of dorsomorphin, a Bmp type I receptor inhibitor, prolonged spermatogonial stem cell (SSC) survival in culture and enhanced germline transmission of the SSCs following transplantation into recipient larvae. In contrast, dorsomorphin inhibited the growth and survival of zebrafish female germline stem cells (FGSCs) in culture. In the presence of dorsomorphin, the spermatogonia continued to express the germ-cell markers dazl, dnd, nanos3, vasa and piwil1 and the spermatogonial markers plzf and sox17 for at least six weeks in culture. Transplantation experiments revealed that 6 week-old spermatogonial cell cultures maintained in the presence of dorsomorphin were able to successfully colonize the gonad in 18% of recipient larvae and produce functional gametes in the resulting adult chimeric fish. Germline transmission was not successful when the spermatogonia were cultured 6 weeks in the absence of dorsomorphin before transplantation. The results indicate that Bmp signaling is detrimental to SSCs but required for the survival of zebrafish FGSCs in culture. Manipulation of Bmp signaling could provide a strategy to optimize culture conditions of germline stem cells from other species

A Zebrafish Cell Culture Assay for the Identification of MicroRNA Targets

MicroRNAs (miRNAs) are endogenous small noncoding RNAs that regulate gene expression at the posttranscriptional level. Studies have shown that zebrafish miRNAs play a key role in embryo development, tissue fate establishment, and differentiation by interacting with specific targets, usually in the 3′UTR of the mRNA. Identification of the target sequence is fundamental to elucidating miRNA function. Since bioinformatics can predict hundreds of potential targets for each miRNA, experimental validation of the actual target site is required. Although recent studies have employed the HEK293 cell line to investigate mammalian miRNA targets, our results have shown that the cell line is not suitable for studies of zebrafish miR-430b miRNA. In this article we describe a convenient in vitro assay system that involves the use of zebrafish cell cultures and a luciferase reporter construct to evaluate miR-430b target sites. The cell culture-based assay could be used to validate target sequences of other zebrafish miRNAs

Heat-treated transgenic embryos developed into infertile male adults.

<p>(A) No difference in appearance or overall size was observed between adult transgenic fish that developed from heat treated embryos and wild-type male. (B) No significant difference in body-weight of 3.5-month-old fish (n = 16 by random sampling) among heat-treat transgenic males, untreated transgenic males and wild-type males, and between the transgenic females and wild-type females. Data shared the same letter (A or B) are not significantly different from each other. Examination of gonadal tissue revealed that (C) A well-developed testis, C1, of untreated male transgenic fish. (D) A well-developed ovary, D1, of untreated female transgenic fish. (E) The gonads of heat-treated transgenic fish developed into a thin filament-like tissue, E1, surrounded by adipocytes. Photomicrograph showing (F) active spermatogenesis of the testis of untreated male transgenic fish, (G) a well-developed ovary with oocytes at different developmental stages of untreated female transgenic fish. (H) The gonad of heat-treated transgenic fish appears to be under-developed and surrounded with large amount of adipocytes without advanced gonadal structure or germ cells. WT: wild type; TG: transgenic; HT: heat treated. Scale bar: 1 cm for A, C–E and 50 µm for F–H. S: spermatozoa.</p

Dorsomorphin increased the growth of spermatogonia in 6 week cultures.

<p>(A) Addition of dorsomorphin significantly (p<0.001) increased the growth of spermatogonia maintained in culture for 6 weeks. (B) Merged bright field and UV photomicrographs showing a colony containing more than 100 DsRed-expressing spermatogonia. (C) RT-PCR analysis of RNA isolated from spermatogonia maintained for 6-weeks in culture in the presence of dorsomorphin, whole testis tissue and feeder cells alone showing expression of germ cell specific marker genes, <i>dazl</i>, <i>dnd</i>, <i>nanos3</i>, <i>vasa</i> and <i>piwil1</i> and spermatogonial markers <i>plzf</i> and <i>sox17.</i> RT: reverse transcription; Data points not sharing a letter (A, B, C, D) are significantly different by Bonferroni–Dunn tests. Scale bar = 20 µm.</p