ABSTRACT
Enzymatic fuel cells (EFCs) use redox enzymes with high electron transfer rates that lead to high power density from bioavailable substrates. However, EFCs are limited by the difficult electrical wiring of the enzymes to the electrode. Therefore, deposition of Co(OH)2 onto graphite oxide (GO) was improved for efficient wiring of the enzymes. The GO/Co(OH)2/chitosan composites were electrodeposited for immobilization of glucose oxidase (GOD) or laccase on an Au electrode, respectively. The electrical properties of the bioelectrode according to cyclic voltammetry were improved using GO/Co(OH)2/chitosan composites. The anode and cathode system was composed of GOD and laccase as biocatalysts and glucose/oxygen as substrates under ambient conditions (pH 7.0 and 25 °C). The EFC using GO/Co(OH)2/chitosan composites with a mediator delivered a high power density of up to 517±3.3 µW/cm² at 0.46 V and open circuit voltage of 0.60 V. These results provide a promising direction for further development and application of EFCs.
Subject(s)
Biosensing Techniques/methods , Enzymes, Immobilized/chemistry , Glucose Oxidase/chemistry , Laccase/chemistry , Carbon/chemistry , Chitosan/chemistry , Cobalt/chemistry , Electrodes , Glucose/chemistry , Graphite/chemistry , Hydroxides/chemistry , Oxidation-Reduction , Oxygen/chemistryABSTRACT
To identify the roles of various circulating cells (eg, endothelial and/or stem and progenitor cells) in angiogenesis, we parabiosed a wild-type syngeneic mouse with a transgenic syngeneic green fluorescent protein mouse. Following the establishment of a common circulation between these parabionts, we investigated acute (7 to 10 days), subacute (2 to 3 weeks), and chronic (4 to 6 weeks) phases of angiogenesis in wild-type mice using wound healing, implanted gel foam fragments, and subcutaneous tumor assays, respectively. We found that under in vitro conditions, circulating murine monocytes expressed F4/80, CD31, and vascular endothelial growth factor receptor 2, but neither CD133 nor von Willebrand factor, whereas murine endothelial cells expressed CD31, vascular endothelial growth factor receptor 2, and von Willebrand factor, but neither CD133 nor F4/80. Immunofluorescence analysis revealed that green fluorescent protein-positive cells in the walls of new vessels in wounds, gel foam blocks, and tumors expressed both F4/80 and CD31, that is, macrophages. Pericytes, cells that express both CD31 and desmin, were found both in the walls of tumor-associated vessels and within tumors. Collectively, these data demonstrate that monocytes (ie, cells that express both CD31 and F4/80) may be recruited to the site of tissue injury and directly contribute to angiogenesis, reaffirming the close relationships between various cell types within the reticuloendothelial system and suggesting possible targets for anticancer treatments.
Subject(s)
Endothelium, Vascular/physiology , Monocyte-Macrophage Precursor Cells/physiology , Monocytes/metabolism , Neoplasms/blood supply , Neoplastic Cells, Circulating/metabolism , Neovascularization, Pathologic/metabolism , Platelet Endothelial Cell Adhesion Molecule-1/metabolism , AC133 Antigen , Acute Disease , Animals , Antigens, CD/metabolism , Antigens, Differentiation/metabolism , Chronic Disease , Female , Fluorescent Antibody Technique , Glycoproteins/metabolism , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Macrophages/metabolism , Mice , Mice, Inbred C57BL , Mice, Transgenic , Peptides/metabolism , Vascular Endothelial Growth Factor Receptor-2/metabolism , Wound Healing , von Willebrand Factor/metabolismABSTRACT
We have identified and cloned a novel toxin gene (tccC1/xptB1) from Xenorhabdus nematophilus strain isolated from Korea-specific entomophagous nematode Steinernema glaseri MK. The DNA sequence of cloned toxin gene (3048 bp) has an open reading frame encoding 1016 amino acids with a predicted molecular mass of 111058 Da. The toxin sequence shares 50-96% identical amino acid residues with the previously reported tccC1 cloned from X. nematophilus, Photorhabdus luminescens W14 P. luminescens TTO1, and Yersinia pestis CO92. The toxin gene was successfully expressed in Escherichia coli, and the recombinant toxin protein caused a rapid cessation in mortality of Galleria mellonella larvae (80% death of larvae within 2 days). Conclusively, the heterologous expression of the novel gene tccC1 cloned into E. coli plasmid vector produced recombinant toxin with high insecticidal activity.
