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Biomedical subjects

M Tsujimoto

Publications and source records attributed to M Tsujimoto.

At least 307 records · Page 17Linked to original sources
PubMed1981

Reactivity of human C-reactive protein with positively charged liposomes.

Interaction of CRP with liposomes was studied by agglutination, complement consumption, and the binding assay. Liposomes composed of phosphatidylcholine and stearylamine were agglutinated with CRP. The interaction of CRP and liposomes was further demonstrated by the consumption of hemolytic complement activity. Stearylamine could be substituted by cetyltrimethylammonium bromide, indicating that positively charged molecules were required for the interaction. Agglutination of liposomes caused by CRP was dependent on the fatty acid composition of phosphatidylcholine, cholesterol content and temperature. Differential scanning calorimetry measurement revealed that both the agglutination of liposomes and the consumption of complement caused by CRP required the fluid state of membranes. Particle electrophoresis measurement showed that stearylamine in fluid state membranes was more dispersed than in rigid state membranes indicating that lateral distribution of stearylamine affected the reactivity of liposomes. The mode of complement activation by the interaction of CRP with positively charged liposomes was similar to that observed in the system of protamine and heparin.

Agglutination Tests↗
PubMed1981

Chemical and biological properties of a peptidoglycan isolated from Treponema pallidum kazan.

A peptidoglycan layer of Treponema pallidum kazan was isolated by solubilization of whole cells with 1% warm sodium dodecyl sulfate and subsequent digestion of an insoluble residue with proteases. Electron microscopy revealed that the peptidoglycan was isolated as a single-layered sacculus of less than 5 nm in thickness, freed from axial filaments and an envelope sheath. An isolated peptidoglycan fraction was mainly composed of glucosamine, muramic acid, alanine, glutamic acid, ornithine, and glycine in molar ratios of 0.65:0.68:1.63:1.00:0.75:1.03. Amino (N)- and carboxyl (C)-terminal amino acid analyses suggested the involvement of at least a part of the glycine residue in cross-linking between the amino group of ornithine residue at one strand of the stem peptide subunit and the carboxyl group of alanine of the neighboring strand. The treponemal peptidoglycan lacked the immunoadjuvant activity both to stimulate antibody production and to induce delayed-type hypersensitivity against ovalbumin, as well as the properties necessary to stimulate guinea pig and mouse splenocytes and guinea pigs peritoneal macrophages, unlike the cell walls or peptidoglycans (group A type of Schleifer and Kandler's classification, Bacteriol. Rev. 36:407-477, 1972) isolated from many bacterial species parasitic to the mammal. However, the peptidoglycan activated the human complement system through the alternative pathway, as well as the classical one, and caused a liberation of 5-hydroxytryptamine in rabbit blood platelets in a similar manner to the cell wall peptidoglycans of both group A and B types.

Amino Acids↗
PubMed1980

C-Reactive protein induced agglutination of lipid suspensions prepared in the presence and absence of phosphatidylcholine.

CRP-induced agglutination of lipid suspensions prepared in the presence and absence of phosphatidylcholine was studied by a newly devised quantitative method. CRP caused as much agglutination of suspensions composed of egg yolk phosphatidylcholine, cholesterol, and Span 60 as of those composed of cholesterol and Span 60, suggesting that phosphocholine residues of phosphatidylcholine are not important as binding sites for CRP. Agglutination of suspensions prepared without phosphatidylcholine was inhibited by phosphocholine, indicating that the inhibition by phosphocholine is non-competitive. Although phosphatidylcholine is not an essential component for agglutination of suspensions, it may modify the mode of interaction of CRP with its binding site on lipid suspensions, since the sensitivity of the agglutination to phosphocholine and the Ca2+ requirement were influenced by the presence of phosphatidylcholine in the suspensions.

C-Reactive Protein↗
PubMed1980

Polyclonal B cell activation by cell wall preparations of gram-positive bacteria. In vitro responses of spleen cells obtained from Balb/c, nu/nu, nu/+, C3H/He, C3H/HeJ and hybrid (DBA/N x Balb/c)F1 mice.

The effects of polyclonal B cell activation (PBA) of cell walls and their cell wall fractions obtained from several kinds of gram-positive bacteria were studied using the anti-sheep red blood cell (SRBC) or anti-trinitrophenylated (TNP) SRBC plaque forming cell (PFC) responses of cultured spleen cells from Balb/c, athymic nu/nu, their littermates (nu/+), C3H/He (LPS-responder), C3H/HeJ (LPS-nonresponder), (CBA/N x Balb/c) F1 male with an X-linked defect in B cell function and the F1 female mice. The cell walls of Staphylococcus epidermidis (ATCC 155), Lactobacillus plantarum (ATCC 8014), Micrococcus lysodeikticus (NCTC 2665), Mycobacterium rhodochrous (ATCC 184), Streptomyces gardneri (ATCC 23911) and Nocardia corynebacteriodes (ATCC 14898) had the ability to induce polyclonal B cell responses in the spleen cells of Balb/c, nu/nu, nu/+, C3H/He and C3H/HeJ mice. The cell wall fractions prepared by enzymatic digestion from the cell walls of S. epidermidis, S. gardneri or N. corynebacteriodes were also capable of inducing polyclonal B cell responses. The responses of spleen cells from (CBA/N x Balb/c) F1 male mice to these active preparations, except the cell walls of M. rhodochrous which possess this ability. The PBA-ability of synthetic peptidoglycan, muramyl dipeptide (N-acetylmuramyl-L-alanyl-D-isoglutamine, MDP), was also examined, and a similar activity was observed in MDP.

Animals↗
PubMed1979

Adjuvant activities in production of reaginic antibody by bacterial cell wall peptidoglycan or synthetic N-acetylmuramyl dipeptides in mice.

This paper is concerned with the adjuvant activity in stimulatory immunoglobulin E production against ovalbumin (OA) by bacterial cell walls, cell wall peptidoglycan (PG), and their PG fragments and synthetic N-acetylmuramyl (MurNAc) dipeptides in A/J mice. A PG isolated from Streptococcus pyogenes, PG subunit polymer and dimer obtained from Staphylococcus epidermidis, and water-soluble fragments of cell walls or PG prepared from Nocardia corynebacteriodes and Streptomyces gardneri were found to enhance both the primary and secondary responses of anti-OA immunoglobulin E antibody production. It was suggested that the PG portion, either intact or highly degraded, was capable of enhancing the immunoglobulin E antibody production, and there was no need for the non-PG moiety or intactness of PG structure for the adjuvant activity. This finding was confirmed and extended by the use of synthetic MurNAc dipeptides. Among eight MurNAc dipeptides tested, MurNAc-l-Ala-d-isoGln, MurNAc-l-Ala-d-Gln, MurNAc-l-Ala-d-Glu, and MurNAc-l-Ser-d-isoGln were found active as an adjuvant in the stimulation of the primary and secondary reaginic anti-OA antibody production in a similar way to the cell wall PG and their fragments. None of the synthetic MurNAc-l-Ala-l-isoGln, MurNAc-l-Ala-l-Gln, MurNAc-l-Ala-l-Glu, and MurNAc-l-Ala-d-isoAsn, on the other hand, stimulated the anti-OA immunoglobulin E antibody production in either primary or secondary response, indicating the importance for the adjuvancy in immunoglobulin E production of the configuration of the glutamic acid residues adjacent to the l-Ala (or l-Ser) in muramyl dipeptides.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1979

Macrophage activation by bacterial cell walls and related synthetic compounds.

Activation of peritoneal macrophages from guinea pigs by various bacterial cell walls, M-1 endo-N-acetylmuramidase enzymatically digested bacterial cell walls and synthetic muramyl dipeptides was studied in terms of stimulation of [14C] glucosamine incorporation. All test bacterial cell wall preparations significantly increased a [14C]glucosamine uptake by the macrophages. Some of the water-soluble M-1 enzyme digests also exerted stimulating effects on macrophages, although the activity of the digests was found to be weaker than those of original cell walls. Furthermore, an adjuvant-active synthetic MurNAc-L-Ala-D-isoGln (MDP) showed a weak but significant activity, whereas an adjuvant-inactive analog, MurNAc-L-Ala-L-iso-Gln, did not show a significant activity, at least with the dose of 100 microgram. Additional studies with 6-O-acyl derivatives of MDP revealed that 6-O-(2-tetradecylhexadecanoyl)-MDP and 6-O-(3-hydroxy-2-tetradecyl-octadecanoyl)-MDP exhibit stronger macrophage-stimulating effects than MDP. It can be concluded from the above findings that MDP is the essential structure responsible for stimulating the activity of cell walls on guinea pig peritoneal macrophages, but it requires a particle state, which results from an additive character of lipophilicity, to exert the activity fully and effectively.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1979

Mitogenic effects of bacterial cell walls, their fragments, and related synthetic compounds on thymocytes and splenocytes of guinea pigs.

Stimulation of [(3)H]thymidine incorporation of thymocytes and splenocytes from guinea pigs by various bacterial cell walls and their peptidoglycans, by enzymatic digests, and by synthetic muramyl dipeptides was studied as an indication of mitogenic activity. Cell wall and peptidoglycan preparations, isolated from 19 strains belonging to 18 different species, definitely increased [(3)H]thymidine incorporation of thymocytes as well as splenocytes, regardless of mycolic acid contents as a non-peptidoglycan component. Both the cell walls from Nocardia corynebacteriodes (containing mycolic acids) and those from Streptomyces gardneri (lacking mycolic acids) showed far stronger mitogenic activities on splenocytes than other cell walls (stimulation index, 25 to 30). Furthermore, water-soluble enzymatic digests, notably the endopeptidase digests, which generally were greater in degree of polymerization of peptidoglycan subunits than the glycosidase digests obtained from representative cell walls, were found to have as distinct a stimulating activity on splenocytes as the original cell walls. In contrast, solubilization of the cell walls by enzymes, irrespective of endopeptidases or glycosidases, was accompanied by disappearance of the mitogenic activity on thymocytes. On the other hand, studies with synthetic 6-O-acyl-MurNAc-l-Ala-d-isoGln preparations (6-O-acyl-MDPs) revealed that 6-O-stearoyl-MDP and 6-O-(2-tetradecylhexadecanoyl)-MDP, unlike MDP, had distinct mitogenic activity on thymocytes, whereas their activity on splenocytes was rather weaker than MDP itself. The findings presented here suggest that MDP is the minimal structure for the mitogenic activities of bacterial cell walls on guinea pig splenocytes, but that MDP, though distinctively active by itself, requires a polymerized form to exert effectively its inherent stimulating activities on splenocytes. On the other hand, on thymocytes, MDP, unless it takes a particular form or has appropriate additive groups, cannot exert its mitogenic activities.

Acetylmuramyl-Alanyl-Isoglutamine↗