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21.
Bioactive recombinant bovine interleukin-18 (rboIL-18) was expressed using a baculovirus system. Normally, IL-18 is translated as a precursor form of a 24kDa polypeptide and processed by IL-1beta converting enzyme (ICE) to a mature bioactive form of 18kDa protein. Hence, to express active form IL-18, we constructed two recombinant baculoviruses containing boIL-18 and human ICE (hICE) genes, respectively, and superinfected these viruses into insect cells. Superinfection of both recombinant viruses into the cells resulted in the expression of a 24kDa precursor form and an 18kDa mature form detectable in the supernatant by immunoblotting using anti-porcine IL-18 antibody. Culture supernatant from the superinfected cells showed a synergistic effect with recombinant boIL-12 for production of interferon-gamma (IFN-gamma) in bovine peripheral mononuclear cells. By addition of histidine hexamer at the C-terminal of boIL-18, the mature IL-18 was purified. Bioactivity remained after purification.  相似文献   
22.
In order to provide background for understanding biological roles of proteoglycans (PG) in developing skeletal muscle, we have isolated and characterized PG in bovine neonatal skeletal muscle. Two types of PG were isolated from skeletal muscle by density gradient ultracentrifugation and ion‐exchange chromatography. One was a small PG (PG‐S) with a molecular size of 100–130 kDa, another was a large PG (PG‐L) with a molecular size of 300–500 kDa. The glycosaminoglycan chains of PG‐S and PG‐L were dermatan sulfate and chondroitin sulfate, respectively, judged by cellulose acetate membrane electrophoresis. Immunoblot assays revealed that both PG bound to type I, II, III and IV collagen, laminin and fibronectin. Unlike PG‐S, PG‐L bound to type V collagen and hyaluronic acid. Small proteoglycans had a core protein of 45 kDa, which reacted with the antibody against the decorin core protein. The N‐terminal amino acid sequence of the PG‐S core protein was consistent with that of decorin from bovine bone and tendon. Thus, PG‐S from neonatal skeletal muscle was identified as decorin in bovines. Immunohistochemical analysis with antibodies against PG‐L and PG‐S demonstrated that PG‐L was located both in the perimysium and endomysium, but PG‐S was localized exclusively in the perimysium. These findings suggest that the characterized PG may have distinct roles in the ECM construction of developing skeletal muscle.  相似文献   
23.
Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.  相似文献   
24.
The constituent subunits of seed storage protein 11S globulin have two disulfide bonds that are common among 11S globulins from legume and nonlegume seeds. In the case of the A1aB1b subunit of soybean 11S globulin, glycinin, Cys12-Cys45 and Cys88-Cys298 are observed by X-ray crystallography. The significance of these two disulfide bonds for structural stability was investigated by mutagenesis of Cys12 to Gly and of Cys88 to Ser. The disulfide bond-deficient mutants C12G and C88S could form the correct conformations identical to that of the wild-type proglycinin except in the vicinities of the mutation sites C12 and C88 as shown by their crystal structures. Thermal stability monitored by differential scanning calorimetry of the mutants indicated that the contribution of these disulfide bonds to the thermal stability of proglycinin A1aB1b is low, although there is a small difference in the extent of the contribution between the two disulfide bonds (Cys12-Cys45 > Cys88-Cys298). The contribution of Cys88-Cys298 to the resistance of proglycinin A1aB1b to proteinase digestion is higher than that of Cys12-Cys45. Possible effects of structure on the different properties of C12G and C88S are discussed.  相似文献   
25.
Precipitation chemistry was discussed from the viewpoint of potential sources for four rural sites where wet-only daily-basis measurement data sets were available during the period from April 1996 to March 1997 in Japan. Annual volume-weighted mean concentrations of nss-SO4 2? and NO3 ? ranged from 18.0 to 34.6 µeq L?1, and from 9.3 to 23.1 µeq L?1, respectively. The degree of neutralization of input acidity in terms of the concentration ratio, [H+] / ([nss-SO4 2?] + [NO3 ?]), ranged from 0.46 to 0.63. This suggests that about half of the input acidity due to H2SO4 and HNO3 was neutralized by NH4 + and nss-Ca2+ to produce the pH values of 4.46 to 4.82 for these sites. Maximum likelihood factor analysis was then performed on the logarithmically transformed daily wet deposition of major ions. Two factors successfully explained a total of about 80% of the variance in the data for each site. Interpreting varimax rotated factor loadings, we could identify two source types: (1) acid source with large loadings on ln(H+), ln(nss-SO4 2?), ln(NO3 ?) and ln(NH4 +), (2) sea-salt source with large loadings on ln(Na+), ln(Cl?), ln(Mg2+) and ln(K+). The rural wet deposition over Japan appears to have a similar structure in terms of the kinds of sources and their relative location.  相似文献   
26.
27.
Two series of combinatorial tripeptide libraries were constructed, based on an antioxidative peptide isolated from a soybean protein hydrolysate. One was a library of 108 peptides containing either His or Tyr residues. Another was a library of 114 peptides related to Pro-His-His, which had been identified as an active core of the antioxidative peptide. The antioxidative properties of these libraries were examined by several methods, such as the antioxidative activity against the peroxidation of linoleic acid, the reducing activity, the radical scavenging activity, and the peroxynitrite scavenging activity. Two Tyr-containg tripeptides showed higher activities than those of two His-containing tripeptides in the peroxidation of linoleic acid. Tyr-His-Tyr showed a strong synergistic effects with phenolic antioxidants. However, the tripeptide had only marginal reducing activity and a moderate peroxynitrite scavenging activity. Cysteine-containing tripeptides showed the strong peroxynitrite scavenging activity. Change of either the N-terminus or C-terminus of Pro-His-His to other amino acid residues did not significantly alter their antioxidative activity. Tripeptides containing Trp or Tyr residues at the C-terminus had strong radical scavenging activities, but very weak peroxynitrite scavenging activity. The present results allow us to understand why protein digests have such a variety of antioxidative properties.  相似文献   
28.
29.
We have investigated 37 minor serogroup Shiga toxin-producing Escherichia coli (STEC) strains other than O157, O26, and O111 isolated from human specimens in Osaka prefecture to determine their serological and biochemical characteristics, virulence-associated genes, and clinical signs in patients. The same serotype strains were genotyped by pulsed-field gel electrophoresis (PFGE). The O antigen of 33 strains were typed into 10 serogroups; O28, O63, O65, O91, O103, O119, O121, O126, O165, and O177, and other 4 strains were not agglutinated with any serum. Four different Shiga toxin (Stx) types (1, 2, 2c, and 2f) were distributed in these isolates. The intimin gene was present in 83.8% of the strains and subtyped into intimin alpha, beta, epsilon, and zeta. STEC O165, O177, and OUT isolated from hemolytic uremic syndrome (HUS) patients revealed atypical biochemical characters; negative reaction for lysine decarboxylase and gas production from glucose. Eleven strains including the isolates from HUS patients generated no colonies on cefixime-tellurite (CT)-sorbitol-MacConkey agar plates, since they showed high sensitivity (MIC 相似文献   
30.
A regression model of wet deposition on rainfall amount for non-seasalt sulfate (nss-SO4 2?) and nitrate (NO3 ?) was applied to a data set obtained through a nationwide survey from April 1989 to March 1993. Wet-only samples on a biweekly basis were collected at 29 sites over Japan. Reparameterized bivariate lognormal distribution was employed to describe the joint distribution of concentration (C) and rainfall amount (R) for each site. Ranges of geometric mean (μD) of biweekly deposition (D = C. R) for each site were 0.54–2.90 meq m?2 for nss-SU4 2?, and 0.21–1.36 meq m?22 for NO3 ?; that of biweekly rainfall amount (μR) was 24.1–78.0 mm. Urban or industrialized areas had high values of μD for these ions. Ranges of estimates of the slope of the regression equation of log(D/μD) on log(R/μR), were 0.45–0.99 for nss-SO4 2?, and 0.35–0.86 for NO3 ?; thus estimates of the slope for nss-SO4 2? tend to be larger than those for NO3 ?. The present analysis, consequently, statistically clarified some differences between the two ions in deposition processes which is understood in the light of current knowledge of atmospheric chemistry.  相似文献   
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