The effects of sodium bisulfite in extraction of PHB by hypochlorite

Summary Molecular weight of PHB becomes low when using a hypochlorite extraction method for PHB separation. This disadvantage was overcome by adding sodium bisulfite which is an anti-oxidant. The molecular weight drop was decreased from 30 % to 14 % by adding sodium bisulfite. It was also found that raising the pH to 12 and the addition of a surfactant resulted in the improvement of the PHB purity.     

Small interfering RNA (siRNA) targetted to Smad3 inhibits transforming growth factor-β signaling

RNA interference has become a powerful tool for silencing of gene expression in mammals and plants. To determine the effect of Smad3 on transforming growth factor-beta signaling, we constructed a small interfering RNA (siRNA) targeted to Smad3. This siRNA inhibited expression of the endogenous Smad3 leading to the prevention of nuclear localization of Smad3. Further, Smad3 siRNA prevented not only anti-proliferative activity of TGF-beta1 but also TGF-beta1-inducible promoter activity.     

Optimization of a Novel Two-step Process Comprising Re-esterification and Transesterification in a Single Reactor for Biodiesel Production Using Waste Cooking Oil

Waste cooking oil (WCO) has attracted attention as a non-edible feedstock for biodiesel. Although an alkali catalyst has several advantages over an acid catalyst in biodiesel production, biodiesel conversion from WCO is only 5.2% when using an alkali catalyst (NaOH), owing to its high free fatty acid (FFA) content of 4.2%. In this study, a novel two-step process in a single reactor, comprised of re-esterification of the FFAs with crude glycerol, using a Tin (II) chloride (SnCl₂) catalyst, and subsequent transesterification with methanol, using an alkali catalyst, was adopted, and each step was optimized. This study revealed that the FFA content after re-esterification should be approximately 1.5%, not only to save glycerol and the catalyst involved in the re-esterification, but also to achieve high biodiesel conversion during the transesterification. An alkaline catalyst was successfully used to produce biodiesel in the second step, and a 92.8% conversion to biodiesel was achieved under the optimized conditions (0.6% catalyst relative to WCO, 0.2mL-methanol/WCO, 70ºC, 3 h). Overall, this novel two-step process achieved highly enhanced biodiesel conversion (4.0% to 92.8%) with significantly reduced reaction time (12 h to 4 h) and methanol requirements (15 mL/g-WCO to 0.2 mL/g-WCO).     

<Emphasis Type="Italic">In vivo</Emphasis> fluorescence imaging to assess early therapeutic response to tumor progression in a xenograft cancer model

Bioimaging technology plays an important role in assessment of therapeutic response in cancer therapy. Here, we report a non-invasive monitoring system for measuring tumor growth by in vivo fluorescence imaging. Target cells for xenograft tumor induction were manipulated by cell-surface fluorescence labelling. Fluorescence was clearly detected in vitro and in vivo without affecting cytotoxicity. Anti-tumor efficacy was evaluated by directly measuring the fluorescence signal of a progressive tumor in a xenograft model. This non-invasive in vivo monitoring system can be used to assess the early response to antitumor therapeutics and may be a valuable tool to replace or complement traditional caliper-based methods for preclinical studies.     

Preparation of immobilized whole cell biocatalyst and biodiesel production using a packed-bed bioreactor

Rhizopus oryzae NBRC 4697 was selected from among promising candidates as a biocatalyst for biodiesel production. This microorganism was immobilized on to polyurethane foam coated with activated carbon for reuse, and, for biodiesel production. Vacuum drying of the immobilized cells was found to be more efficient than natural or freeze-drying processes. Although the immobilized cells were severely inhibited by a molar ratio of methanol to soybean oil in excess of 2.0, stepwise methanol addition (3 aliquots at 24-h feeding intervals) significantly prevented methanol inhibition. A packed-bed bioreactor (PBB) containing the immobilized whole cell biocatalyst was then operated under circulating batch mode. Stepwise methanol feeding was used to mitigate methanol inhibition of the immobilized cells in the PBB. An increase in the feeding rate (circulating rate) of the reaction mixture barely affected biodiesel production, while an increase in the packing volume of the immobilized cells enhanced biodiesel production noticeably. Finally, repeated circulating batch operation of the PBB was carried out for five consecutive rounds without a noticeable decrease in the performance of the PBB for the three rounds.     

CIIA induces the epithelial-mesenchymal transition and cell invasion

Epithelial-mesenchymal transition (EMT) and the acquisition of invasive potential are key events in tumor progression. We now show that CIIA, originally identified as an anti-apoptotic protein, induces the EMT and promotes cell migration and invasion. Ectopic expression of CIIA induced down-regulation of E-cadherin and claudin-1 as well as up-regulation of N-cadherin in MDCK cells. It also disrupted the differentiated epithelial morphology of MDCK cells grown in three-dimensional Matrigel cultures as well as increased the migration and invasion of MDCK cells in vitro. Furthermore, depletion of endogenous CIIA by RNA interference inhibited the migration and invasion of HeLa cells, and this inhibition was abolished by RNA interference-mediated depletion of claudin-1. These results suggest that CIIA functions as an inducer of cell invasion, and this effect is mediated, at least in part, through down-regulation of claudin-1.     

Effects of <Emphasis Type="Italic">Escherichia coli</Emphasis> RraA Orthologs of <Emphasis Type="Italic">Vibrio vulnificus</Emphasis> on the Ribonucleolytic Activity of RNase E In Vivo

RraA is a recently discovered protein inhibitor of RNase E that catalyzes the initial step in the decay and processing of numerous RNAs in Escherichia coli. In the genome of Vibrio vulnificus, two open reading frames that potentially encode proteins homologous to E. coli, RraA-designated RraAV1 and RraAV2, have respectively 80.1% and 59.0% amino acid identity to RraA. The authors report that coexpression of RraAV1 protein in E. coli cells overproducing RNase E rescued these cells from growth arrest and restored their normal growth, whereas coexpression of RraAV2 protein further inhibited the growth of E. coli cells, whose growth was already impaired by overproduction of RNase E. Analyses of the steady-state level of various RNase E substrates indicated that the coexpression of RraAV1 more efficiently inhibited RNase E action than coexpression of RraA, and consequently resulted in the more increased abundance of each RNA species tested in vivo. The inhibitory effect by RraAV2 coexpression on RNase E was observed only in the case of trpA mRNA, indicating the possibility of RNA substrate-dependent inhibition of RraAV2 on RNase E. The findings suggest that these regulators of ribonuclease activity have both a conserved inhibitory function and a differential inhibitory activity on RNase E-like enzymes across the species.