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1.
Antigen-induced production of migration inhibitory factor (MIF) by sensitized lymphocytes requires macrophages to effectively stimulate lymphocytes with soluble antigen in vitro. The present study showed that macrophage-depleted lymphocytes of sensitized guinea pigs could be activated with antigens when the culture supernatant of peritoneal adherent cells pulse-stimulated with a macromolecular fraction of bacterial lipopolysaccharide (LPS) was added to the lymphocyte culture. The apparent macrophage-replacing activity was found in the fraction which emerged slightly ahead of serum albumin upon gel filtration of the culture supernatant, and the activity was shown to be destroyed by heating at 65 °C for 30 min or by trypsin digestion. These results appeared to show that the activity was due to a protein component, most probably released from macrophages. Two-step culture experiments revealed that the soluble factor should be present in the early stage of the culture to activate the macrophage-depleted immune lymphocytes with antigen, as well as in the later stage when the presence of antigen in the medium is no longer required. Furthermore, the factor was shown to act in the activation of a T-cell-enriched fraction of immune lymphocytes. The factor appeared to be playing some essential role in making an antigenic stimulus effective for the activation of immune lymphocytes. 相似文献
2.
D A McMillen J J Volwerk J Ohishi M Erion J F Keana P C Jost O H Griffith 《Biochemistry》1986,25(1):182-193
A series of amine-specific reagents based on the benzaldehyde reactive group have been synthesized, characterized, and used to study beef heart cytochrome c oxidase reconstituted in phospholipid bilayers. The series contained three classes of reagents: lipid-soluble phosphodiesters having a single hydrocarbon chain, phospholipid analogues, and a water-soluble benzaldehyde. All reagents were either radiolabeled or spin-labeled or both. The Schiff bases formed by these benzaldehydes with amines were found to be reversible until the addition of the reducing agent sodium cyanoborohydride, whereas attachment of lipid-derived aliphatic aldehydes was not readily reversible in the absence of the reducing agent. The benzaldehyde group provides a convenient method of controlling and delaying permanent attachment to integral membrane proteins until after the reconstitution steps. This ensures that the lipid analogues are located properly to identify amine groups at the lipid-protein interface rather than reacting indiscriminately with amines of the hydrophilic domains of the protein. The benzaldehyde lipid labels attach to cytochrome c oxidase with high efficiency. Typically, 20% of the amount of lipid label present was covalently attached to the protein, and the number of moles of label incorporated per mole of protein ranged from 1 to 6, depending on the molar ratios of label, lipid, and protein. The efficiency of labeling by the water-soluble benzaldehyde was much less than that observed for any of the lipid labels because of dilution effects, but equivalent levels of incorporation were achieved by increasing the label concentration. Electron spin resonance spectra of a nitroxide-containing phospholipid analogue covalently attached to reconstituted cytochrome c oxidase exhibited a large motion-restricted component, which is characteristic of spin-labeled lipids in contact with the hydrophobic surfaces of membrane proteins. The line shape and splittings were similar for covalently attached label and label free to diffuse and contact the protein molecules in the bilayer, providing independent evidence that the coupling occurs at the protein-lipid interface. The distribution of the benzaldehyde reagents attached to the polypeptide components of cytochrome c oxidase was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The labeling pattern observed for the lipid analogues was not affected by the presence of the nitroxide moiety on the acyl chains but was dependent on the molar ratio of labeling reagent to protein.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
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5.
Nitric Oxide Induces Phytoalexin Accumulation in Potato Tuber Tissues 总被引:22,自引:0,他引:22
We investigated whether nitric oxide (NO) radical could inducephytoalexin production. Treatment of potato tuber tissues with1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC-18), anNO-releasing compound, induced the accumulation of the potatophytoalexin rishitin. This induction was inhibited by carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide(carboxy-PTIO), an NO-specific scavenger, or by Tiron, a radicalscavenger, suggesting a phytoalexin inducing activity for NO. (Received December 7, 1995; Accepted January 4, 1996) 相似文献
6.
Kazuhito Ohishi Yasuyuki Kurimoto Norimitsu Inoue Yuichi Endo Junji Takeda Taroh Kinoshita 《Genomics》1996,34(3):340
Many eukaryotic proteins are bound to the plasma membrane via a glycosylphosphatidylinositol (GPI) anchor. Its core backbone, which is conserved in different organisms, is synthesized in the endoplasmic reticulum by the sequential addition of glycan components to phosphatidylinositol. One of the human GPI synthesis genes,PIGF(phosphatidylinositol glycan complementation class F), which is involved late in the synthesis pathway, has been cloned. In this study, we isolated complementary and genomic clones ofPigf,a murine counterpart ofPIGF. Pigfencodes a 219 amino acid protein that complements a class F mutation. ThePigfgene consists of six exons spanning 30 kb and was mapped to chromosome 17 at 17E4–E5. These features are very similar toPIGF,thus demonstrating the interspecies conservation of structure, function, gene organization, and genetic locus between these GPI synthesis genes. The results also extend a region in murine distal chromosome 17 that is syntenic to human chromosome 2p16–p22. 相似文献
7.
Kazuhito Hisatsune Takehiro Iguchi Yuji Haishima Norihiko Tamura Seiichi Kondo 《Microbiology and immunology》1993,37(2):143-147
The chemical properties of a lipopolysaccharide (LPS) isolated from a new O-antigenic form (O13) of Vibrio parahaemolyticus were investigated. The LPS contained glucose, galactose, L -glycero-D -manno-heptose and glucosamine. 2-Keto-3-deoxy-octonate (KDO) was not detected in the LPS by the periodate-thiobarbituric acid test (Weissbach's reaction) under conventional hydrolysis conditions. Instead, phosphorylated KDO (X1 and X2) was found in its strong-acid hydrolysate. This sugar composition was identical to that of V. parahaemolyticus O3, O5 and O11 LPS, indicating that, based on the sugar composition, O13 LPS belongs to Chemotype III to which O3, O5 and O11 belong. In addition, structural study demonstrated the presence of KDO 4-phosphate in its inner-core region. 相似文献
8.
1. The holoenzyme of D-amino acid oxidase [D-amino acid: O2 oxidoreductase (deaminating), EC 1.4.3.3] was found to combine with 1-anilinonaphthalene-8-sulfonate without liberation of its coenzyme, FAD. No energy transfer interaction was found to occur between the bound dye and FAD of the holoenzyme. On the other hand, when the apoenzyme was bound to the dye and then to FAD, energy transfer interaction between the bound dye and bound FAD was observed. In both cases, the dye competes with the substrate, D-alanine. It is concluded that the dye bound to the holoenzyme is oriented in such a special manner that the mutual orientation factor between the dye and FAD becomes very small in magnitude. 2. When the apoenzyme combined with the dye, the monomer-dimer equilibrium of the apoenzyme shifted towards the dimer. On the other hand, 4-monobenzoylamido-4'-aminostilbene-2,2'-disulfonate combined with the apoenzyme to induce monomerization. 相似文献
9.
Y Tamura M Kijima K Ohishi T Takahashi S Suzuki M Nakamura 《Journal of general microbiology》1992,138(3):537-542
Five monoclonal antibodies (mAbs) directed against the flagellin of Clostridium chauvoei were used to analyse the structural and antigenic characteristics on the bacterial flagellar surface. Immune electron microscopy showed that three protective mAbs recognized the surfaced-exposed epitopes on the flagellar filament of this bacteria. In contrast, two non-protective mAbs recognized internal epitopes of the flagellar filament. These findings have been confirmed by ELISA using mAbs absorbed with whole cells of C. chauvoei possessing flagella. Competitive binding assays showed that protective mAbs indicated reciprocal competition, while each of the non-protective mAbs had topographically distinct epitopes. Moreover, immunoblotting analysis with cyanogen-bromide-cleaved flagellin showed that protective mAbs may preferentially recognize conformational epitopes, whilst one of the non-protective mAbs may recognize a linear and conformation-independent epitope in the flagellin of C. chauvoei. 相似文献
10.
Masahiko Sone Kazuhito Totsune Kazuhiro Takahashi Makoto Ohneda Keiichi Itoi Osamu Murakami Kaoru Yoshinaga Toraichi Mouri 《Peptides》1991,12(6):1333-1335
The presence of immunoreactive porcine brain natriuretic peptide in rat tissues was studied with a specific radioimmunoassay for porcine brain natriuretic peptide-26. The cross-reactivity of the antiserum used was less than 0.001% with rat atrial natriuretic peptide, rat brain natriuretic peptide-32 and rat brain natriuretic peptide-45. Immunoreactive porcine brain natriuretic peptide was detectable in various tissues of the rat, and high concentrations of immunoreactive porcine brain natriuretic peptide were found in the brain and cardiac atrium, with the highest level in the hypothalamus (159±30 fmol/gram wet tissue, mean±SEM, n=4). Reverse phase high performance liquid chromatography showed that the immunoreactive porcine brain natriuretic peptide of the whole brain and heart extracts eluted mainly at an identical position to synthetic porcine brain natriuretic peptide-26. These findings indicate that porcine brain natriuretic peptide-like substance, distinct from rat brain natriuretic peptide, is present in high concentrations in the rat brain and cardiac atrium. 相似文献