Immunostimulatory activities of monoglycosylated α-d-pyranosylceramides

We compared the immunostimulatory effects of chemically synthesized α-galactosylceramides (α-GalCers), α-glucosylceramides (α-GluCers), 6″-monoglycosylated α-GalCer and 6″- or 4″-monoglycosylated α-GluCer and made the following observations: (1) the length of the fatty acid side chain in the ceramide portions greatly affects the immunostimulatory effects of α-GalCers and α-GluCers; (2) the configuration of the 4″-hydroxyl group of the inner pyranose moiety plays an important role in the immunostimulatory effects of monoglycosylated α- -pyranosylceramides; (3) the free 4″-hydroxyl group of the inner pyranose of monoglycosylated α- -pyranosylceramides plays a more important role in their immunostimulatory effects than the free 6″-hydroxyl group.     

Involvement of L-Type-Like Amino Acid Transporters in S-Nitrosocysteine-Stimulated Noradrenaline Release in the Rat Hippocampus

Abstract: Nitrogen oxides, such as nitric oxide, have been shown to regulate neuronal functions, including neurotransmitter release. We investigated the effect of S-nitroso-l -cysteine (SNC) on noradrenaline (NA) release in the rat hippocampus in vivo and in vitro. SNC stimulated [³H]NA release from prelabeled hippocampal slices in a dose-dependent manner. SNC stimulated endogenous NA release within 30 min to almost five times the basal level in vivo (microdialysis in freely moving rats). In a Na⁺-containing Tyrode's buffer, SNC-stimulated [³H]NA release was inhibited 30% by the coaddition of l -leucine. In the Na⁺-free, choline-containing buffer, SNC-stimulated [³H]NA release, which was similar to that in the Na⁺-containing buffer, was inhibited markedly by l -leucine, l -alanine, l -methionine, l -phenylalanine, and l -tyrosine. The effects of the other amino acids examined were smaller or very limited. The effect of l -leucine was stronger than that of d -leucine. A specific inhibitor of the L-type amino acid transporter, 2-aminobicyclo[2.2.1]-heptane-2-carboxylate (BCH), inhibited the effects of SNC on [³H]NA release in the Na⁺-free buffer. Uptake of l -[³H]leucine into the slices in the Na⁺-free buffer was inhibited by SNC, BCH, and l -phenylalanine, but not by l -lysine. The effect of SNC on cyclic GMP accumulation was not inhibited by l -leucine, although SNC stimulated cyclic GMP accumulation at concentrations up to 25 µM, much less than the concentration that stimulates NA release. These findings suggest that SNC is incorporated into rat hippocampus via the L-type-like amino acid transporter, at least in Na⁺-free conditions, and that SNC stimulates NA release in vivo and in vitro in a cyclic GMP-independent manner.     

Immunoblotting of mite aeroallergens collected with an indoor Burkard air sampler

We examined the kinetics of airborne levels of mite allergen particles in a house by combined use of an indoor Burkard air sampler and immunoblotting. Airborne mite allergens collected on the Burkard sampling tape were transferred onto a nitrocellulose membrane, reacted with mouse monoclonal anti-mite allergen (Der pI) antibody, then treated with alkaline phosphatase conjugated anti-mouse IgG. Finally, the blotted allergen on the membrane was reacted with BCIP/NBT phosphatase, and purple spots visible by the naked eye were produced. The shape of the spots was observed under a microscope, and the spot area was measured by an image processor. This technique might be useful for analyzing the behavior of airborne allergen particles in indoor environments.     

Analysis of the NH2-Terminal 83rd Amino Acid of Escherichia coli GyrA in Quinolone-Resistance

Artificial mutations of Gyrase A protein (GyrA) in Escherichia coli by site-directed mutagenesis were generated to analyze quinolone-resistant mechanisms. By genetic analysis of gyrA genes in a gyrA temperature sensitive (Ts) background, exchange of Ser at the NH₂-terminal 83rd position of GyrA to Trp, Leu, Phe, Tyr, Ala, Val, and Ile caused bacterial resistance to the quinolones, while exchange to Gly, Asn, Lys, Arg and Asp did not confer resistance. These results indicate that it is the most important for the 83rd amino acid residue to be hydrophobic in expressing the phenotype of resistance to the quinolones. These findings also suggest that the hydroxyl group of Ser would not play a major role in the quinolone-gyrase interaction and Ser83 would not interact directly with other amino acid residues.     

Novel preparation method for surfactant-coated enzymes using W/O emulsion

Summary A novel preparation method for surfactant-coated enzymes has been developed using a W/O emulsion. The enzymatic activity of chymotrypsin in isooctane significantly increased with the coating of surfactants. The surfactant-coated chymotrypsin showed a high enzymatic activity for amidation, although powdered chymotrypsin did not show the activity. Further, the coated enzyme showed a remarkably high storage stability.     

Auxin-Induced Changes in the Molecular Weight Distribution of Cell Wall Xyloglucans in Avena Coleoptiles

The effect of auxin on the molecular weight (Mw) distributionof cell wall xyloglucans was investigated by gel permeationchromatography using coleoptile segments of Avena sativa L.cv. Victory, and the following results were obtained.

1. The water-insoluble hemicellulose (HC-A) mainly consisted ofxyloglucans. Iodine staining method revealed that relativelylarge amounts of xyloglucans were present in the water-solublehemicellulose (HC-B) and water-soluble polysaccharide (WS) fractions.
2. IAA did not cause remarkable changes in xyloglucan contentsin the hemicellulose, but significantly increased the xyloglucancontent in the WS fraction.
3. IAA substantially decreased theweight-average Mw of HC-A. Thiseffect became apparent within30 min of the incubation period,and was not affected by the0.15 M mannitol or 2% sucrose applied.Hydrogen ions also causeda decrease in the weight-average Mwof HC-A; its effect beingreversible.
4. Neither IAA nor hydrogen ions caused any remarkablechangesin the weightaverage Mw of water-soluble xyloglucansin theHC-B.

These results suggest that cell wall xyloglucans have an importantrole in auxininduced cell wall loosening in oat coleoptile cells. (Received May 10, 1984; Accepted August 20, 1984)     

Growth Regulation of Dark-grown Dwarf Barley Coleoptile by the Endogenous IAA Content

Growth curves of dark-grown coleoptiles of 11 isogenic coleoptilardwarf strains of barley (Hordeum vulagare L. cv. Akashinriki:uzu, 5, 77, 97, 105, 125, 131, 133, 136, 145 and 148) were simulatedwith a logistic equation and the endogenous IAA contents ofthe barley strains were determined. Growth analysis of the dwarfbarley coleoptiles revealed that the final coleoptile lengthwas correlated with the growth rate on the 2nd day after germination(r=0.897), when the growth rate was about maximum. The endogenousIAA Content of the barley strains, measured fluorometrically,indicated that on the 2nd day, the dwarf strains contained lessendogenous IAA than the normal Strain. The IAA content on the2nd day was correlated to the growth rate on the 2nd day (r=0.907,except for Strain 145) and the final coleoptile length (r=0.933,except for strains 77 and 145). The correlation, however, wasnot significant on the 3rd day. These results suggested thatthe dwarfism of the dark-grown coleoptiles of the barley Strainsexamined is primarily controlled by the endogenous IAA content. ¹ Present address: Department of Biology, Faculty of Science,Osaka City University, Osaka 558, Japan. (Received February 1, 1982; Accepted April 13, 1982)     

Genetic polymorphism of the complement C2 in Japanese

Summary Genetic polymorphism of the second component of human complement (C2) was investigated in 521 unrelated healthy adult Japanese using isoelectric focusing in polyacrylamide gel followed by a specific hemolytic overlay method. Besides the phenotypes reported previously (C, AC and BC), a relatively infrequent double-banded phenotype (tentatively named A'C) was observed. Moreover, a homozygous variant (A) and a heterozygous double variant (AB) were observed. The estimated frequencies for the common allele. C2 ² (=C2 ¹ ), and the variant alleles, C2 ^A , C2 ^B (=C2 ² ) and C2 ^A were 0.939, 0.034, 0.022, and 0.006, respectively.The results of further typing for HLA-A,-B,-C specificities indicated the presence of significant associations of C2 ^A with HLA-B15 and with A26, and of C2 ^B with HLA-Bw61. These findings support our previous observation that in Japanese there are allelic combinations showing linkage disequilibrium between C2 and HLA loci which are different from those in Caucasians, and that the C2 structural locus is more closely linked to HLA-B than to HLA-A.C2 hemolytic activities of each phenotypes were assayed. The mean activity of type AC sera was significantly higher than that of type C or type BC, while there were no differences in the activities among the types C, BC or A'C.Also presented are two pedigrees demonstrating the segregation of C2 with HLA alleles in which a homozygous C2A or C2B individual was observed.