Lennart Lindqvist

Origin of esterases in human whole saliva.

Whole saliva of 59 healthy persons was used for determination of esterase activity. The pattern of esterase was studied by means of isoelectrofocusing on thin-layer acrylamide gels. The esterases found in whole saliva are suggested to be derived from the cells of the tissue in the oral cavity. This origin is indicated (e.g.) by comparison between isolectrophoretic esterase patterns of whole saliva, submandibular saliva, gingival biopsy and fibroblast culture. Antisera against partially purified saliva esterases were produced in rabbits. These sera, used in immunoelectro-osmophoresis, gave esterase-active immunoprecipitate against whole saliva, the water-soluble materials of disrupted gingival biopsy and fibroblast culture, but not against the material of the bacteria, Streptococcus sanguis, Strptococcus mutans, Streptococcus mitis, Actinomyces viscosus and Lactobacillus fermentum.

The distribution of proteolytic and alkaline phosphatase activities in human saliva treated with sodium deoxycholate

Sodium deoxycholate was used to release peptidase and alkaline phosphatase activities from saliva sediment. The degree of the release was determined at a variety of detergent concentrations and incubation periods. By use of 0.4% of this detergent 80% of the alkaline phosphatase found in the sediment was released. A twofold increase in peptidase in the soluble fraction (10,000 g supernatant) and a 10% increase in protein resulted in the same concentration of sodium deoxycholate. The distribution of the enzymes in saliva supernatant and the enzymes released from sediment were determined on the substrates gelatin, poly-L-lysine HBr, haemoglobin, a-N-benzoyl-L-arginine ethyl ester-HCl, p-tosyl-L-arginine methyl ester-HCl, L-lysine-p-nitroanilide HBr and p-nitrophenyl phosphate. The study indicates that the peptidase(s) soluble in human saliva without detergent are derived from saliva sediment.

Determination of the absolute configuration of sugar residues using gas chromatography: Method with potential for elimination of references

The absolute configuration of a sugar can be determined by gas-liquid chromatography of the acetylated or trimethylsilylated dithioacetals from 1-phenylethanethiol. The isolation of both enantiomers of 1-phenylethanethiol is also described. Using the acetates and both thiol reagents the absolute configuration of C-2 can be determined, provided it is a hydroxyl group, with great certainty. A new way of determining the absolute configuration of sugars, without references, is thereby provided. The sugars analysed include aldoses, deoxyaldoses, 2-acetamido-2-deoxyaldoses and uronic acids. The analysis is made using columns with non-chiral stationary phase and the electron impact mass spectra of the acetylated and trimethylsilylated bis(1-phenylethyl)dithioacetals are described.

Separation of acyclic derivatives of sugar enantiomers using gas chromatography on chiral stationary phases of permethylated α-, β- and γ-cyclodextrin

Gas-liquid chromatography on monosaccharide single peak derivatives have been run in order to improve methods for the determination of absolute configuration. Eight out of eleven investigated enantiomeric pairs of trifluoroacetylated alditols or aldose diethyl dithioacetals were separated using capillary columns containing chiral stationary phases of permethylated α-cyclodextrin (α-Dex 120), β-cyclodextrin (β-Dex 120) and γ-cyclodextrin (γ-Dex 120).

Effect of beta-lactamase inhibitors on beta-lactamases from anaerobic bacteria

Three beta-lactamase inhibitors in clinical use — clavulanic acid, sulbactam and tazobactam — were investigated for their activity on beta-lactamases fromBacteroides uniformis, Clostridium butyricum andFusobacterium nucleatum. Purification of the beta-lactamases was carried out by anion-exchange chromatography, gel filtration and FPLC. The inactivation of beta-lactamase activity was determined spectrophotometrically with nitrocefin as substrate. Various concentrations of the inhibitors were preincubated at 30 °C together with the enzyme for different periods of time before determination of the beta-lactamase activity. The three beta-lactamases tested were more susceptible to tazobactam than to clavulanic acid and sulbactam. Clavulanic acid and sulbactam reduced the enzyme activity of theBacteroides uniformis beta-lactamase more effectively than theClostridium butyricum andFusobacterium nucleatum beta-lactamases.