Generation of a different type of beta-kallikrein from porcine pancreatic alpha-kallikrein by the action of chymotrypsin--observation of proteolytic processing occurring around "kallikrein autolysis loop" region

The generation of a different type of beta-kallikrein, designated C beta-kallikrein, from alpha-kallikrein by chymotryptic action was ascertained by the following observations: 1) When alpha-kallikrein was incubated with chymotrypsin, an increase of esterolytic activity of kallikrein was observed. 2) In sodium dodecyl sulfate polyacrylamide gel electrophoresis, C beta-kallikrein was found to be different from the beta-kallikrein obtained from alpha-kallikrein by tryptic digestion, and was designated T beta-kallikrein. 3) N-Terminal amino acid sequence analyses of internal light and heavy chains of C beta-kallikrein indicated that N-termini of the light and the heavy chains were isoleucine and lysine, respectively, and that the heavy chain had most of the "kallikrein autolysis loop" sequence in its N-terminal end. In the case of T beta-kallikrein, N-termini of the light and the heavy chains were isoleucine and alanine, respectively, and the light chain retained the "kallikrein autolysis loop" region in its C-terminal end. These observations demonstrated that C beta-kallikrein was different from the beta-kallikrein prepared from autolyzed pancreas, A beta-kallikrein, which had lost the "kallikrein autolysis loop" sequence. Structural differences of the above four kallikreins (alpha-, T beta-, C beta-, and A beta-) result in somewhat different enzyme properties. The kinetic constants for the hydrolysis of synthetic substrates (N alpha-benzoyl-L-arginine ethyl ester and N alpha-tosyl-L-arginine methyl ester) of these kallikreins differed from each other, and inhibitory profiles against alpha 1-antitrypsin were also different.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sonochemical preparation of composite nanoparticles of Au/gamma-Fe2O3 and magnetic separation of glutathione

We prepared Au/gamma-Fe2O3 composite nanoparticles by sonochemically reducing Au(III) ions employing no stabilizer in the aqueous solution to form stable Au nanoparticles and allowing them to attach onto the surface of gamma-Fe2O3 particles with an average size of 21 nm. Size of the formed Au nanoparticle depended on the initial concentration of Au(III) ions. The number of the Au nanoparticles, supported on each gamma-Fe2O3 particle was controlled by changing the relative amounts of Au(III) ions and gamma-Fe2O3 particles. The composite nanoparticles exhibited a high affinity with glutathione, a tripeptide with mercapto group so that separation and manipulation of glutathione in aqueous solutions could be performed by application of external magnetic field. Because the surfaces of the Au nanoparticles were not shielded by any stabilizers, or naked, sonochemically prepared Au/gamma-Fe2O3 composite nanoparticles seemed to show stronger affinity to the glutathione than those by the radiochemical method.     

Tumor-infiltrating effector cells of alpha-galactosylceramide-induced antitumor immunity in metastatic liver tumor

BACKGROUND: alpha-Galactosylceramide (alpha-GalCer) can be presented by CD1d molecules of antigen-presenting cells, and is known to induce a potent NKT cell-dependent cytotoxic response against tumor cells. However, the main effector cells in alpha-GalCer-induced antitumor immunity are still controversial. METHODS: In order to elucidate the cell phenotype that plays the most important role in alpha-GalCer-induced antitumor immunity, we purified and analyzed tumor-infiltrating leukocytes (TILs) from liver metastatic nodules of a colon cancer cell line (Colon26), comparing alpha-GalCer- and control vehicle-treated mice. Flow cytometry was performed to analyze cell phenotype in TILs and IFN-gamma ELISA was performed to detect antigen-specific immune response. RESULTS: Flow cytometry analysis showed a significantly higher infiltration of NK cells (DX5+, T cell receptor alphabeta (TCR)-) into tumors in alpha-GalCer-treated mice compared to vehicle-treated mice. The DX5+TCR+ cell population was not significantly different between these two groups, indicating that these cells were not the main effector cells. Interestingly, the CD8+ T cell population was increased in TILs of alpha-GalCer-treated mice, and the activation level of these cells based on CD69 expression was higher than that in vehicle-treated mice. Moreover, the number of tumor-infiltrating dendritic cells (DCs) was increased in alpha-GalCer-treated mice. IFN-gamma ELISA showed stronger antigen-specific response in TILs from alpha-GalCer-treated mice compared to those from vehicle-treated mice, although the difference between these two groups was not significant. CONCLUSIONS: In alpha-GalCer-induced antitumor immunity, NK cells seem to be some of the main effector cells and both CD8+ T cells and DCs, which are related to acquired immunity, might also play important roles in this antitumor immune response. These results suggest that alpha-GalCer has a multifunctional role in modulation of the immune response.     

A series of trinuclear Cu(II)Ln(III)Cu(II) complexes derived from 2,6-Di(acetoacetyl)pyridine: synthesis, structure, and magnetism

A series of trinuclear Cu(II)Ln(III)Cu(II) complexes with the bridging ligand 2,6-di(acetoacetyl)pyridine have been prepared by one-pot reaction with Cu(NO(3))(2).3H(2)O and Ln(NO(3))(3).nH(2)O in methanol. X-ray crystallographic studies for all the complexes indicate that two L(2)(-) ligands selectively sandwich two Cu(II) ions with the 1,3-diketonate entities and one Ln(III) ion with the 2,6-acetylpyridine entity to form a trinuclear CuLnCu core bridged by the enolate oxygen atoms. Cryomagnetic properties of the complexes are studied with respect to the electronic structure of the Ln ion.     

Resonance-enhanced two-photon sum-frequency generation in NiO and KNiF<Subscript>3</Subscript>

Resonance-enhanced sum-frequency generation is introduced as a novel tool for investigation of magnetically ordered compounds. A tunable laser at frequency ₁ is used to excite an intermediate electronic transition resonantly while a second laser at frequency ₂ is used to scan the nonlinear spectrum at ₁+₂. The technique is particularly useful for investigation of centrosymmetric compounds since resonance enhancement at ₁ leads to large nonlinear signals even in the case of weakly allowed nonlinear processes. The technique is demonstrated on antiferromagnetic NiO and KNiF₃ and also shown to be useful for investigation of samples with large thickness or absorption. PACS 42.65.Ky; 78.20.Ls; 42.62.FiThis revised version was published in October 2004 with a correction to the name of Takuya Satoh.     

Theoretical study of the optical manipulation of semiconductor nanoparticles under an excitonic resonance condition

We theoretically study the mechanical interaction between radiation and a semiconductor nanoparticle, based on a microscopic model of confined excitons. The exerted force is calculated by using the Maxwell stress tensor expressed in terms of the microscopic response field. The numerical demonstrations clarify the following: (1) The enhancement of the force by using electronic resonance is remarkable for a particle with a radius of less than 100 nm for semiconductor materials. (2) The spectral peak position of the exerted force is considerably sensitive to nanoscale-size changes which would be useful for highly accurate size-selective manipulation.     

Larval ultrastructure of Parasarcophaga dux (Thomson) (Diptera: Sarcophagidae)

Ultrastructure of all larval instars of Parasarcophaga dux (Thomson), a common flesh fly species in Thailand, is presented using scanning electron microscopy. Special attention is given to the structure of anterior and posterior spiracles since these are important features used to differentiate between other sarcophagids. Each anterior spiracle in second and third instars has a single row of papillae varying in number from 14 to 17. The posterior spiracular discs have incomplete peritremes, with a prominent inner arc. Three long, narrow spiracular slits are oriented more or less vertically in each spiracular disc of third instar. Posterior spiracular hairs lack extensive branching and emanate approximately midway down the length of each slit. Microscopic morphology of the mouthhooks markedly differs between the first and second instars. The structure of these mouthhooks supports this fly species as being necrophagous or capable of producing myiasis.     

Nomura algebras of nonsymmetric Hadamard models

We show that the Nomura algebra of the nonsymmetric Hadamard model coincides with the Bose–Mesner algebra of the directed Hadamard graph.