Granulated hydroxyapatite: Preparation and chromatographic properties

Mazin, A L; Sulimova, G.E.; Vanyushin, B. F.

doi:10.1016/0003-2697(74)90333-9

Cited by 57 publications

(8 citation statements)

References 11 publications

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“…In the adherence assay, the granulated form of HA (Sigma; type III) was used in place of the conventional bead form. The granulated HA consisted of spherical aggregates (diameter, 200 to 250 m) of HA crystals and contained about 1% silicic acid as the aggregating agent (31).…”

Section: Methodsmentioning

confidence: 99%

Active release of bound antibody by Streptococcus mutans

Lee

1995

Infect Immun

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Previous studies have shown that Streptococcus mutans is capable of releasing many surface protein antigens, particularly antigen P1. Antigen P1 is immunodominant and has been implicated in adherence of S. mutans to the acquired pellicles. The purpose of this study is to investigate the significance of release of this antigen by the cells. S. mutans NG8 (serotype c) was incubated with an anti-P1 rabbit immunoglobulin G (IgG) or a human colostral IgA which contains natural anti-P1 activity. Results indicated that the bound antibodies were released by the cells in a pH-and time-dependent manner. The optimal pH for release was between 6 and 8, and the release rate reached a plateau in 1 h at 37؇C. The release of bound antibodies was considered an active process, since heat-killed cells remained capable of antibody binding but failed to release the antibodies. The release was also dependent on the age of the culture, with early-exponential-phase cells releasing the maximum amount of bound IgG. The released IgG was isolated by polyethylene glycol precipitation and protein A-Sepharose column chromatography and found to be associated with antigen P1, indicating that the antibodies were released together with the antigen in the form of immune complexes. The binding of S. mutans by secretory IgA (SIgA) inhibited the adherence of the cells to salivary agglutinin-coated hydroxylapatite. However, when the SIgA-coated S. mutans was allowed to release the bound antibodies, the inhibitory effect of SIgA on adherence was abrogated. These results suggest that S. mutans is capable of shedding surface-bound antibodies in the form of antibody-antigen immune complexes. Such an action may be a strategy employed by the cells to counter the neutralizing effect of naturally occurring antibodies in the oral cavity.

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Section: Methodsmentioning

confidence: 99%

Active release of bound antibody by Streptococcus mutans

Lee

1995

Infect Immun

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“…The active fractions were pooled, dialyzed extensively against 10 mM potassium phosphate buffer pH 7.0, containing 5 mM 2-mercaptoethanol and 5% glycerol. A column (2 cm 0 x 5 cm) of hydroxylapatite (prepared according to Mazin et al, (1974) was poured and equilibrated in dialysis buffer. The diluted enzyme was adsorbed to hydroxylapatite and eluted with 50 mM potassium phosphate buffer (pH 7.0), containing 5 mM 2-mercaptoethanol and 5% glycerol.…”

Section: Uv-specific Endonucleasementioning

confidence: 99%

Physico-chemical and biological study of excision-repair of UV - irradiated øX174 RF DNA in vitro

Heijneker

1975

Nucl Acids Res

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We have studied excision-repair of UV-irradiated phiX174 RFI DNA in vitro with UV-specific endonuclease from Micrococcus luteus (UV-endo), DNA polymerase I from Escherichia coli and DNA ligase from phage T4 infected E. coli. Excision-repair was measured a) by physico-chemical methods, i.e. by determination of the conversion of RF I DNA into RF II DNA by UV-endo and by the subsequent conversion of RF II DNA ligase, b) by biological methods i. e. by measuring the ability of the reaction product to form phages upon incubation with spheroplasts from the appropriate strains of E. coli. Using the first method, we have shown, that more than 90% of the pyrimidine dimers can be repaired in vitro; with the latter method we have shown, that the molecules which are repaired as defined by method a) have regained full biological activity. Exonuclease III was found to be not essential for excision-repair in vitro and also did not stimulate repair. From this result we conclude that UV-endo generates 3'OH endgroups, in agreement with results obtained by Hamilton et al. (1974). The usefulness of the method presented in this paper with regard to the study of excision-repair is discussed.

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“…This extract was then applied to a column (2.5 by 90 cm) of Ultrogel AcA34, and 100 8-ml fractions were eluted with phosphate buffer. Fractions with the highest specific activities were obtained after a 250-ml amount had eluted; these were combined, concentrated as before, and chromatographed on granulated hydroxylapatite which was prepared by the procedure of Mazin et al (12). Enzyme was eluted from the hydroxylapatite column (3 by 23 cm) by using successive 100ml portions of 0.1, 0.2, 0.3, and 0.4 M K+ phosphate buffer, pH 7.1; enzyme was eluted with 0.3 M buffer, and fractions were combined, concentrated, and chromatographed on a column (1.7 by 17 cm) of phenyl Sepharose C1-4B.…”

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confidence: 99%

Catabolism of tryptophan, anthranilate, and 2,3-dihydroxybenzoate in Trichosporon cutaneum

Anderson¹,

Dagley²

1981

J Bacteriol

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Trichosporon cutaneum degraded L-tryptophan by a reaction sequence that included L-kynurenine, anthranilate, 2,3-dihydroxybenzoate, catechol, and fl-ketoadipate as catabolites. All of the enzymes of the sequence were induced by both L-tryptophan and salicylate, and those for oxidizing kynurenine and its catabolites were induced by anthranilate but not by benzoate; induction was not coordinate. Molecular weights of 66,100 and 36,500 were determined, respectively, for purified 2,3-dihydroxybenzoate decarboxylase and its single subunit. Substrates for this enzyme were restricted to benzoic acids substituted with hydroxyl groups at C-2 and C-3; no added coenzyme was required for activity. Partially purified anthranilate hydroxylase (deaminating) catalyzed the incorporation of one atom of 180, derived from either '"02 or H2150, into 2,3-dihydroxybenzoic acid. In a previous study of the catabolism of aromatic acids in Trichosporon cutaneum (1), we showed that the enzyme 2,3-dihydroxybenzoate decarboxylase (EC 4.1.1.46) is strongly derepressed in cells grown on 2-hydroxybenzoate (salicylate), despite the fact that the substrate of this enzyme is not a catabolite of salicylate. An explanation for this observation has emerged from the present work. We have shown that salicylate derepresses the whole series of enzymes, including 2,3-dihydroxybenzoate decarboxylase, which the organism uses for degrading L-tryptophan. This catabolic pathway was found to be similar to that demonstrated by previous workers (5, 20, 21) for tryptophan catabolism in Aspergillus niger and Claviceps paspali. MATERIALS AND METHODS Organism and cell extracts. The organism used, T. cutaneum, was grown in shake cultures at 300C as described earlier (1, 16) with single aromatic acids (0.05%), including L-tryptophan, serving as major sources of carbon. For preparing cell extracts that contained about 10 mg of protein per ml, the organism was grown to the stationary phase in 16-liter batches under vigorous forced aeration. The inoculum used was 1 liter of a shake culture. For purification of 2,3dihydroxybenzoate decarboxylase, larger quantities of cells (150 g [wet weight]) were grown at the expense of salicylate (2-hydroxybenzoate) in a 100-liter fermentor which was provided with a mechanical stirrer and aeration and contained 90 liters of growth medium.

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Granulated hydroxyapatite: Preparation and chromatographic properties

Cited by 57 publications

References 11 publications

Active release of bound antibody by Streptococcus mutans

Active release of bound antibody by Streptococcus mutans

Physico-chemical and biological study of excision-repair of UV - irradiated øX174 RF DNA in vitro

Catabolism of tryptophan, anthranilate, and 2,3-dihydroxybenzoate in Trichosporon cutaneum

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