Selective isolation of N-blocked peptides by isocyanate-coupled resin

We developed a method for selective isolation of N-blocked peptides from a complex mixture such as an enzymatic digest of a protein. The approach is based on a newly designed isocyanate-resin (resin-NCO), which specifically reacts with alpha-amino or imino groups. This method, then, permits the isolation of N-blocked peptides, even those containing Lys, from a peptide mixture as intact forms by trapping N-free peptides via covalent bonding to the resin-NCO. The present study demonstrates the performance of this method for the selective isolation of N-blocked peptides by applying it to several peptide mixtures, including proteolytic digests.     

Consideration on calibration and correction factors of an Hp10 chamber for different radiation qualities and angles of incidence

This paper presents the characterisation performed at IRSN (France) of an H(p)(10) chamber in terms of calibration coefficient and correction factors for the radiation qualities of ISO narrow spectrum series. The chamber response, expressed in H(p)(10) using conversion coefficients h(p)(K)(10; N, alpha) listed in ISO 4037-3 in the energy range from 30 to 1250 keV and for angles of incidence between 0 and 70 degrees, was found to be within approximately 10%. However, for photon energies <30 keV, an overresponse of the chamber that could reach 100% was observed. Nevertheless, this overresponse was reduced to 25% using the conversion coefficients estimated at Physikalisch-Technische Bundesanstalt (PTB). This implies that the X-ray spectra produced by the IRSN X-ray units are very similar to those produced by PTB, both containing a little bit more high-energy photons than the spectra used in ISO 4037-3. The dose rate dependence of the chamber tested by gamma radiation from (60)Co sources was found to be within 2% in the range of 0.3 mSv h(-1) to 1 Sv h(-1). The H(p)(10) chamber can measure directly the conventional true value of H(p)(10) after calibration by a reference laboratory, and can be used for transferring H(p)(10) reference quantities from a reference laboratory.     

Increased Indoleamine 2,3-Dioxygenase Levels at the Onset of Sjögren’s Syndrome in SATB1-Conditional Knockout Mice

Sjögren’s syndrome (SS) is a chronic autoimmune disease characterized by dysfunction of salivary and lacrimal glands, resulting in xerostomia (dry mouth) and keratoconjunctivitis sicca (dry eyes). Autoantibodies, such as anti-SSA and anti-SSB antibodies, are hallmarks and important diagnostic factors for SS. In our previous study, we demonstrated that SS-like xerostomia was observed in SATB1 conditional knockout (SATB1cKO) mice, in which the floxed SATB1 gene was specifically deleted in hematopoietic cells as early as 4 weeks of age. In these mice, autoantibodies were not detected until 8 weeks of age in SATB1cKO mice, although exocrine gland function reached its lowest at this age. Therefore, other markers may be necessary for the diagnosis of SS in the early phase. Here, we found that mRNA expression of the interferon γ (IFN-γ) gene and the IFN-responsive indoleamine 2,3-dioxygenase (IDO) gene is upregulated in the salivary glands of SATB1cKO mice after 3 and 4 weeks of age, respectively. We detected l-kynurenine (l-KYN), an intermediate of l-tryptophan (l-Trp) metabolism mediated by IDO, in the serum of SATB1cKO mice after 4 weeks of age. In addition, the upregulation of IDO expression was significantly suppressed by the administration of IFN-γ neutralizing antibodies in SATB1cKO mice. These results suggest that the induction of IFN-dependent IDO expression is an initial event that occurs immediately after the onset of SS in SATB1cKO mice. These results also imply that serum l-KYN could be used as a marker for SS diagnosis in the early phases of the disease before autoantibodies are detectable.     

Structure and dyeability of Bombyx mori silk fibers with different filament sizes

This study deals with the analysis of structure, physical properties, and dyeing behavior of silk fibers with different filament sizes. Fine and coarse silk fibers were obtained from Akebono and Ariake cocoon varieties, respectively. Both samples exhibited a fairly similar x-ray crystallinity, while the degree of molecular orientation increased with decreasing the fiber size. Tensile strength and energy of fine silk fibers were significantly higher, while elongation at break did not change in relation to the fiber size. Fine silk fibers exhibited a slightly higher thermal stability, as shown by the upward shift of both the DSC decomposition temperature and the TMA final extension step at above 300°C. The TGA and DMA (E″) patterns remained unchanged regardless of fiber size. The amino acid analysis confirmed the absence of any difference of chemical structure between fine and coarse silk fibers, the content of acidic, basic, and other characteristic amino acid residues being exactly the same. Accordingly, both samples adsorbed the same amount of hydrochloric acid. Ex-haustion dyeing tests with various direct, acid, and reactive dyes showed the occurrence of appreciable differences in the perceived color between fine and coarse silk fibers. The size of color difference was quantitatively evaluated by reflectance measurements and discussed in relation to silk fiber morphology, structure, as well as dyeing conditions. The kinetics of diffusion of two model dyes was not significantly affected by the different fiber size and structure. © 1996 John Wiley & Sons, Inc.     

Self-written waveguide on a VCSEL-emitting window using a photomask transfer method

This study is focused on a self-written waveguide (SWW) fabricated using a new photomask transfer method. With the proposed photomask transfer method, an SWW array was successfully fabricated on vertical-cavity surface-emitting laser (VCSEL) diode-emitting windows. It was found that the output power of a VCSEL having the SWW increased as compared to that of VCSEL without the SWW. We have confirmed that the optical output is independent of the placement of the emitting window inside the SWW. Optical coupling between an SWW and a graded-index multimode fiber was also demonstrated.     

Prevalence of Arcobacter species in retail meats and antimicrobial susceptibility of the isolates in Japan

A survey was conducted to examine the prevalence of Arcobacter species among meat samples and to investigate the antimicrobial susceptibility of the isolates in Japan. In 1998 and 1999, samples of beef (n=90), pork (n=100) and chicken meat (n=100) were purchased from seven retail shops. Arcobacter species were isolated from 2.2%, 7.0% and 23.0% of beef, pork and chicken meat samples, respectively. The rate of isolations in chicken meats was shown to be significantly higher than those of beef and pork. Species-specific polymerase chain reaction (PCR) demonstrated that the most dominant Arcobacter species was Arcobacter butzleri among the isolates examined. Multiple contaminations with different Arcobacter species were observed in 5% of the chicken samples. Almost all the strains tested showed resistance to vancomycin (100%) and methicillin (97.5%). Strains resistant to cephalothin, sulfamethoxazole–trimethoprim, nalidixic acid and chloramphenicol were detected at the rate of 81.1%, 67.2%, 53.5% and 24.6%, respectively. All Arcobacter strains examined were susceptible to ampicillin, tetracycline, streptomycin and kanamycin.     

Introduction of Cu(II) complex into transparent synthetic resin and optical function of the resin as a near-infrared ray cutoff filter

A mole ratio method was conducted to determine a necessary condition to solubilize Cu(II) ion into an organic solvent. Copper benzoate anhydrous (CB) and acetone was used as a Cu(II) ion supplier and a solvent, respectively. Methacryloyloxy-ethyl phosphate (PMOE) and di(2-ethylhexyl) phosphate (DIEHP) were used asligands for solubilization. Cu(II) ion was solubilized with only two PMOE molecules, although six molecules were needed for DIEHP. PMOE formed an intermediate layer which surrounded the Cu(II) ion with two molecules between the ion and solvent and made it possible to solubilize Cu(II) ion into the organic solvent. In the case of DIEHP, however, six molecules were needed to form such a layer for solubilization. Furthermore, Cu(II) ion was introduced homogeneously into poly(methyl methacrylate) (PMMA) by copolymerization of PMOE with MMA, although the polymer was opaque in the case of DIEHP. The ligand having a methacryloyl group was considered to participate in the polymerization process, which avoided exclusion of the Cu(II) complex from polymer phase. The intermediate zone formed by PMOE was considered to keep compatibility of Cu(II) ion with the polymer matrix even after polymerization. The near-infrared ray cutting-off filter made of resin was realized by introducing Cu(II) ion at higher concentration through complexation with the proper ligand. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:903–912, 1998     

Structure and properties of tussah silk fibers graft-copolymerized with methacrylamide and 2-hydroxyethyl methacrylate

Tussah silk fibers were graft-copolymerized with methacrylamide (MAA) and 2-hydroxyethyl methacrylate (HEMA) in aqueous media, using a chemical redox system as an initiator. High weight gain values were obtained with both grafting agents (up to 175%). The extent of homopolymerization was negligible for the MAA grafting system over the entire range of monomer–silk ratios examined, while polymer deposition on the fiber surface occurred when the HEMA–silk ratio exceeded 0.5% (w/w). The moisture content of poly(MAA)-grafted silk fibers was enhanced by grafting. Breaking load, elongation at break, and energy decreased at low weight gain (0–20%) and then remained rather constant. The DSC curves of poly(MAA)-grafted silk showed a new endotherm at about 280°C, due to the melting of poly(MAA) chains. The loss modulus peak of poly(HEMA)-grafted silk fibers broadened and shifted to a lower temperature, showing a tendency to split into two peaks at high weight gain. On the other hand, grafting with poly(MAA) induced a noticeable upward shift of the loss peak. The TMA curves showed that grafting with poly(MAA) resulted in a higher extent of fiber contraction from room temperature to about 250°C. Moreover, the intensity of the final contraction step at about 350°C decreased with increasing weight gain and shifted to a lower temperature. The Raman spectra of grafted fibers were characterized by overlapping of the characteristic lines of both silk fibroin and polymer, the latter showing an intensity proportional to the amount of weight gain. Among the conformationally sensitive vibrational modes of tussah silk fibroin, the amide III range was significantly modified by grafting with both poly(MAA) and poly(HEMA). © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1393–1403, 1998     

Chemical modification of wool fibers with acid anhydrides

Wool fibers were chemically modified by reaction with succinic and glutaric anhydrides. The weight gain (and acyl content) increased with increasing the reaction temperature (65–80°C) and time (1–2 h), attaining 18.9% (158.9 mol/10⁵ g) and 23% (163.9 mol/10⁵ g) for succinylated and glutarylated wool, respectively. Changes in the amino acidic pattern of acylated wool, i.e., decrease of basic amino acid residues and formation of ornithine, were observed by acid hydrolysis. The X‐ray diffraction profiles of modified wool fibers remained essentially unchanged, suggesting that the crystalline structure was not affected by reaction with acid anhydrides. The degree of molecular orientation of acylated wool slightly decreased, especially at high weight gain. The viscoelastic response of wool modified with succinic and glutaric anhydrides was characterized by a shift to a lower temperature of both the drop of the storage modulus and the peak of the loss modulus. These features are indicative of a higher mobility of the keratin chians in the amorphous and crystalline domains. In fact, it is suggested that the chemical agent diffused into the accessible parts of α‐crystallites, reaching the available reactive sites. This did not cause changes in the crystalline pattern of wool, but resulted in a different thermal behavior of fibers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1573–1579, 1999     

Structure and physical properties of silk fibroin/polyacrylamide blend films

This article deals with the characterization of blend films obtained by mixing silk fibroin (SF) and polyacrylamide (PAAm). The DSC curves of SF/PAAm blend films showed overlapping of the main thermal transitions characteristic of the individual polymers. The exothermic peak at 218°C, assigned to the β‐sheet crystallization of silk fibroin, slightly shifted to a lower temperature by blending. The weight‐retention properties (TG) of the blend films were intermediate between those of the two constituents. The TMA response was indicative of a higher thermal stability of the blend films, even at low PAAm content (≤25%), the final breaking occurring at about 300°C (100°C higher than pure SF film). The peak of dynamic loss modulus of silk fibroin at 193°C gradually shifted to lower temperature in the blend films, suggesting an enhancement of the molecular motion of the fibroin chains induced by the presence of PAAm. Changes in the NH stretching region of silk fibroin were detected by FTIR analysis of blend films. These are attributable to disturbance of the hydrogen bond pattern of silk fibroin and formation of new hydrogen bonds with PAAm. The values of strength and elongation at break of blend films slightly improved at 20–25% PAAm content. A sea–island structure was observed by examining the air surface of the blend films by scanning electron microscopy. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1563–1571, 1999