Construction and Characteristics of a Recombinant Single- Chain Antibody Fragment against Bacterial Type III Secretion

Pseudomonas aeruginosa, a Gram-negative pathogen, causes life-threatening infections. Lung injury and the development of sepsis depend largely on expression of the virulence genes associated with the type III secretion system of this bacterium. The type III secretion system functions as a molecular syringe to deliver type III secretory toxins directly into the cytosol of eukaryotic cells and also acts to inhibit innate immune mechanisms, thereby preventing bacterial clearance. Antibodies against PcrV, the cap structure in the translocational needle of type III secretory apparatus of P. aeruginosa, block toxin translocation of the type III secretion system. We have been investigating the therapeutic use of a recombinant anti-PcrV single-chain antibody. In this chapter, as a preliminary step toward an antibody-based immunotherapy against bacterial infections, we summarize our experience of constructing a recombinant single-chain antibody (called scFv166), in which the heavy (VH) and light chain (VL) variable regions of the anti-PcrV monoclonal IgG are joined by a flexible peptide linker. The practical methodologies used to make recombinant scFv166 against a bacterial protein component are described in detail

Martensitic Transformation and Metamagnetic Transition in Co-V-(Si, Al) Heusler Alloys

This study investigates the crystal structure, martensitic transformation behavior, magnetic properties, and magnetic-field-induced reverse martensitic transformation of Co64V15(Si21–xAlx) alloys. It was found that by increasing the Al composition, the microstructure changes from the martensite phase to the parent phase. The crystal structures of the martensite and parent phases were determined as D022 and L21, respectively. Thermoanalysis and thermomagnetization measurements were used to determine the martensitic transformation and Curie temperatures. Both the ferromagnetic state of the parent phase and that of the martensite phase were observed. With the increasing Al contents, the martensitic transformation temperatures decrease, whereas the Curie temperatures of both the martensite and parent phases increase. The spontaneous magnetization and its composition dependence were also determined. The magnetic-field-induced reverse martensitic transformation of a Co64V15Si7Al14 alloy under pulsed high magnetic fields was observed. Moreover, using the results of the DSC measurements and the pulsed high magnetization measurements, the temperature dependence of the transformation entropy change of the Co-V-Si-Al alloys was estimated

Martensitic Transformation and Metamagnetic Transition in Co-V-(Si, Al) Heusler Alloys

This study investigates the crystal structure, martensitic transformation behavior, magnetic properties, and magnetic-field-induced reverse martensitic transformation of Co64V15(Si21–xAlx) alloys. It was found that by increasing the Al composition, the microstructure changes from the martensite phase to the parent phase. The crystal structures of the martensite and parent phases were determined as D022 and L21, respectively. Thermoanalysis and thermomagnetization measurements were used to determine the martensitic transformation and Curie temperatures. Both the ferromagnetic state of the parent phase and that of the martensite phase were observed. With the increasing Al contents, the martensitic transformation temperatures decrease, whereas the Curie temperatures of both the martensite and parent phases increase. The spontaneous magnetization and its composition dependence were also determined. The magnetic-field-induced reverse martensitic transformation of a Co64V15Si7Al14 alloy under pulsed high magnetic fields was observed. Moreover, using the results of the DSC measurements and the pulsed high magnetization measurements, the temperature dependence of the transformation entropy change of the Co-V-Si-Al alloys was estimated

Pseudomonas aeruginosa Type III Secretory Toxin ExoU and Its Predicted Homologs

Pseudomonas aeruginosa ExoU, a type III secretory toxin and major virulence factor with patatin-like phospholipase activity, is responsible for acute lung injury and sepsis in immunocompromised patients. Through use of a recently updated bacterial genome database, protein sequences predicted to be homologous to Ps. aeruginosa ExoU were identified in 17 other Pseudomonas species (Ps. fluorescens, Ps. lundensis, Ps. weihenstephanensis, Ps. marginalis, Ps. rhodesiae, Ps. synxantha, Ps. libanensis, Ps. extremaustralis, Ps. veronii, Ps. simiae, Ps. trivialis, Ps. tolaasii, Ps. orientalis, Ps. taetrolens, Ps. syringae, Ps. viridiflava, and Ps. cannabina) and 8 Gram-negative bacteria from three other genera (Photorhabdus, Aeromonas, and Paludibacterium). In the alignment of the predicted primary amino acid sequences used for the phylogenetic analyses, both highly conserved and nonconserved parts of the toxin were discovered among the various species. Further comparative studies of the predicted ExoU homologs should provide us with more detailed information about the unique characteristics of the Ps. aeruginosa ExoU toxin

Pd2MnGa Metamagnetic Shape Memory Alloy with Small Energy Loss

Abstract Metamagnetic shape memory alloys (MMSMAs) are attractive functional materials owing to their unique properties such as magnetostrain, magnetoresistance, and the magnetocaloric effect caused by magnetic‐field‐induced transitions. However, the energy loss during the martensitic transformation, that is, the dissipation energy, Edis, is sometimes large for these alloys, which limits their applications. In this paper, a new Pd2MnGa Heusler‐type MMSMA with an extremely small Edis and hysteresis is reported. The microstructures, crystal structures, magnetic properties, martensitic transformations, and magnetic‐field‐induced strain of aged Pd2MnGa alloys are investigated. A martensitic transformation from L21 to 10M structures is seen at 127.4 K with a small thermal hysteresis of 1.3 K. The reverse martensitic transformation is induced by applying a magnetic field with a small Edis (= 0.3 J mol−1 only) and a small magnetic‐field hysteresis (= 7 kOe) at 120 K. The low values of Edis and the hysteresis may be attributed to good lattice compatibility in the martensitic transformation. A large magnetic‐field‐induced strain of 0.26% is recorded, indicating the proposed MMSMA's potential as an actuator. The Pd2MnGa alloy with low values of Edis and hysteresis may enable new possibilities for high‐efficiency MMSMAs